U.S. patent application number 11/931918 was filed with the patent office on 2011-07-14 for quick-donning full face oxygen mask with inflatable harness and soft foldable lens.
This patent application is currently assigned to BE INTELLECTUAL PROPERTY, INC.. Invention is credited to Gary R. Hannah, Gregory R. Jones, Thomas K. McDonald, Randy G. Stratman.
Application Number | 20110168182 11/931918 |
Document ID | / |
Family ID | 23228991 |
Filed Date | 2011-07-14 |
United States Patent
Application |
20110168182 |
Kind Code |
A1 |
McDonald; Thomas K. ; et
al. |
July 14, 2011 |
QUICK-DONNING FULL FACE OXYGEN MASK WITH INFLATABLE HARNESS AND
SOFT FOLDABLE LENS
Abstract
A mask and harness system for use in providing breathing oxygen
and protection from pollutants for the eyes and respiratory system
as might be encountered in high altitude aviation environments. In
one preferred embodiment, the mask system has a face seal, a soft
flexible lens, a pneumatically-actuated harness, and a regulator
with microphone to control the flow of oxygen and to facilitate
communications in aircraft flight decks and other aircraft
compartments. The system is designed for required five-second
donning with one hand and because of the flexible lens, is capable
of storage in the relatively preferred on crowded flight decks. It
is connected to an oxygen source and, optionally, with aircraft
communications. The regulator controls the flow rate of oxygen to
the wearer based on altitude and physiological requirements. The
regulator includes a valve for purging the condensation-prone moist
gases from the lens area and provides positive pressure in the
mask. A second preferred embodiment molds the lens and mask seal of
a single material having sufficient optical quality and flexibility
to accomplish both purposes.
Inventors: |
McDonald; Thomas K.;
(Overland Park, KS) ; Hannah; Gary R.; (Merriam,
KS) ; Stratman; Randy G.; (Prairie Village, KS)
; Jones; Gregory R.; (Lenexa, KS) |
Assignee: |
BE INTELLECTUAL PROPERTY,
INC.
Wellington
FL
|
Family ID: |
23228991 |
Appl. No.: |
11/931918 |
Filed: |
October 31, 2007 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11657303 |
Jan 24, 2007 |
|
|
|
11931918 |
|
|
|
|
10671379 |
Sep 25, 2003 |
7178526 |
|
|
11657303 |
|
|
|
|
10214033 |
Aug 7, 2002 |
6672307 |
|
|
10671379 |
|
|
|
|
09560011 |
Apr 27, 2000 |
6443155 |
|
|
10214033 |
|
|
|
|
09362264 |
Jul 28, 1999 |
6070580 |
|
|
09560011 |
|
|
|
|
08820079 |
Mar 19, 1997 |
5957132 |
|
|
09362264 |
|
|
|
|
08316422 |
Sep 30, 1994 |
5664566 |
|
|
08820079 |
|
|
|
|
Current U.S.
Class: |
128/205.25 |
Current CPC
Class: |
A62B 18/02 20130101;
B64D 10/00 20130101; A62B 18/084 20130101; A62B 18/082 20130101;
A62B 25/005 20130101; B64D 2231/025 20130101 |
Class at
Publication: |
128/205.25 |
International
Class: |
A62B 18/08 20060101
A62B018/08 |
Claims
1. A quick-donning full face oxygen mask for use in oxygen depleted
environments and environments contaminated by smoke or other
pollutants comprising: a flexible face seal, said flexible face
seal including an interior, and a pliable, flexible periphery
conformable to a wearer's face, said flexible face seal further
including a plurality of mounting points for an inflatable harness
attached to said flexible face seal, said flexible face seal
further including an oxygen supply regulator removably attached to
said flexible face seal; a flexible optical lens of optical quality
disposed in said flexible face seal, said flexible face seal having
means for mounting said flexible optical lens in a region of the
mask adapted to overlie the eyes of the wearer, said flexible
optical lens surrounded by said face seal, said flexible optical
lens having a rolled configuration for storage and an unrolled
configuration capable of deflecting to conform to a wearer's face
and to said rolled configuration; said flexible optical lens
sealingly attached to said flexible face seal at its periphery to
thereby bond and seal said flexible optical lens to said face seal;
said inflatable harness including at least one lateral wrap-around
elastomeric tube connected to said oxygen regulator and supplied
oxygen by said oxygen regulator, said at least one lateral
wrap-around elastomeric tube extending around the rear of the head
of the wearer and attached to said flexible face seal by said
plurality of mounting points; said oxygen regulator being connected
to the interior of said flexible face seal to provide breathing gas
to said wearer, a portion of said breathing gas being conducted to
an interior surface of said flexible optical lens to prevent
fogging, said flexible face seal and said flexible optical lens
being of sufficient flexibility to allow said mask to be rolled for
storage.
2. The quick-donning full face oxygen mask of claim 1, wherein said
flexible optical lens is formed of clear silicone.
3. The quick-donning full face oxygen mask of claim 1, wherein said
flexible optical lens is coated with a scratch resistant
additive.
4. The quick-donning full face oxygen mask of claim 3, wherein said
flexible optical lens is coated with a scratch resistant coating of
clear urethane.
5. The quick-donning full face oxygen mask of claim 1, wherein said
flexible optical lens is formed of a clear peroxide cured molding
grade silicone.
6. The quick-donning full face oxygen mask of claim 1, wherein said
flexible mask assembly is formed of a flexible, optically
transparent plastic.
7. The quick-donning full face oxygen mask of claim 1, wherein said
flexible mask assembly is formed of a flexible, optically
transparent silicone.
8. The quick-donning full face oxygen mask of claim 1, wherein said
flexible mask assembly comprises a face seal formed of
silicone.
9. The quick-donning full face oxygen mask of claim 1, wherein said
flexible mask assembly comprises an inflatable harness formed of
silicone tubing.
10. The quick-donning full face oxygen mask of claim 1, wherein
said flexible mask assembly and said flexible optical lens are
formed as a single piece of transparent silicone.
11. The quick-donning full face oxygen mask of claim 10, wherein
said flexible mask assembly and said flexible optical lens are
formed of an optical quality clear silicone.
12. The quick-donning full face oxygen mask of claim 11, wherein
said flexible optical quality lens is coated with an abrasion
resistant material.
13. The quick-donning full face oxygen mask of claim 1, wherein
said flexible optical quality lens provides a wide field of view to
the wearer.
14. The quick-donning full face oxygen mask of claim 1, wherein
said inflatable harness further comprises adjustable straps
attached to said at least one lateral wrap-around elastomeric tube
and to said flexible face seal at positions which allow the
adjustment of the inflatable harness for size and comfort by the
wearer.
15. The quick-donning full face oxygen mask of claim 1, wherein
said inflatable harness comprises a central circular elastomeric
tube connected to said at least one lateral wrap-around elastomeric
tube.
16. The quick-donning full face oxygen mask of claim 1, wherein
said at least one lateral wrap-around elastomeric tube comprises a
plurality of connectors to form a central circular portion of said
at least one lateral wrap-around elastomeric tube.
17. The quick-donning full face oxygen mask of claim 1, wherein
said inflatable harness comprises top and bottom lateral
wrap-around elastomeric tubes.
18. The quick-donning full face oxygen mask of claim 17, further
comprising a vertical tube connecting said top and bottom lateral
wrap-around elastomeric tubes.
19. The quick-donning full face oxygen mask of claim 1, wherein
said inflatable harness comprises first and second lateral
wrap-around elastomeric tubes held in place in a
cross-configuration by a retainer.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This is a continuation of Ser. No. 11/657,303, filed Jan.
24, 2007, which is a continuation of Ser. No. 10/671,379, filed
Sep. 25, 2003, now U.S. Pat. No. 7,178,526, which is a continuation
of Ser. No. 10/214,033 filed Aug. 7, 2002, now U.S. Pat. No.
6,672,307, which is a continuation of Ser. No. 09/560,011 filed
Apr. 27, 2000, now U.S. Pat. No. 6,443,155, which is a continuation
of Ser. No. 09/362,264 filed Jul. 28, 1999 now U.S. Pat. No.
6,070,580, which is a continuation of Ser. No. 08/820,079 filed
Mar. 19, 1997 now U.S. Pat. No. 5,957,132, which is a divisional of
Ser. No. 08/316,422 filed Sep. 30, 1994, now U.S. Pat. No.
5,664,566.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to face mask systems for protection
from atmospheric pollutants and the supply of oxygen to the mask
wearer and more particularly to mask systems to supply oxygen for
use in oxygen-depleted environments during aircraft decompression,
smoke from onboard fires, airborne debris or other toxic gases
which may enter the aircraft flight deck or other crew
compartments.
[0004] 2. Description of Related Art
[0005] In the course of aircraft operation, various personnel,
including but not limited to pilots, navigation officers, and other
flight crew personnel, may need a mask system to provide breathing
oxygen and also to provide protection from smoke from onboard fires
and other possible airborne eye and lung irritants which may enter
the crew compartment(s). There is a requirement in the commercial
aviation industry that the masks designed for crew usage be capable
of donning in five seconds or less, be able to be donned over
eyeglasses and be capable of supplying oxygen consistent with
physiological demands at altitudes up to 40,000 feet.
[0006] Provisions for stowage of the mask must be sensitive to both
the quick-donning requirements and the very limited space and
volume available in the aircraft flight decks, and it is
particularly desirable that mask storage be compact enough that it
is easily placeable within the flight deck in a position close to
and convenient to the crewmember when he or she is seated at his or
her station. It is also highly desirable that the mask be capable
of accommodating a wide variety of facial sizes and configurations
while still adequately sealing the face from the external
environment.
[0007] Since the mask is to be used by crewmembers in an
environment that may be highly stressful, both in terms of the
visual tasks and the visibility afforded in the presence of smoke
and the like, it is important that the mask provide an acceptable
level of optical clarity and freedom from distortion consistent
with the other desirable characteristics of the mask. Another
desirable characteristic is that the mask provide, to the extent
possible for a stowable mask, protection from impingement on the
face of airborne debris and pollutants, and protection of the eyes
in particular from the windborne type of debris that could be
present from an explosive decompression or other breach of the
windshield system in a large aircraft. Prior art crew masks have
addressed these problems with masks incorporating rigid lenses
mounted in an otherwise flexible mask, or by combinations of
goggles and oxygen masks. While these masks have been functionally
useful, they offer disadvantages in field of view, adaptability to
a wide range of head sizes and configurations, the ability to be
rapidly donned over glasses and stowability in small areas in the
cockpit of the aircraft near the crewmember. The present invention
provides improved solutions to all of these problems.
SUMMARY OF THE INVENTION
[0008] The present invention is for a stowable mask that meets a
number of stringent and difficult environmental and functional
requirements for use in circumstances that typically exist in a
pressurized aircraft after decompression or in the event of an
in-flight emergency that causes smoke or debris to intrude into the
flight deck. In the event that such an event occurs, it is
recognized that the continued ability of the flight crew to operate
with a high degree of competence is critical to the prevention of
loss of life and property, and thus the availability of such masks
and their functionality is highly desirable for such aircraft.
[0009] Because of the recognition of the benefits of such mask
systems, it has also become common to require the availability of
such masks to many who may during the course of their occupations
be exposed to such hazards and who must perform critical tasks
during such exposure. Particularly in the case of aircraft, it is
highly desirable that such masks take up the smallest amount of
stowage space prior to use in order to make them available to the
seated user at his station and to avoid taking up the limited space
in the flight deck. Thus, the instrument panel or side panels at
the crew station are preferred locations for this equipment. It is
important that the mask be stowed in a manner which allows for the
quick-donning and also does not interfere with normal aircraft
operation. As the mask is likely to be installed on both existing,
as well as new aircraft, it is an important feature of the
invention that the mask fit in existing cavities already defined
for such equipment.
[0010] The present invention provides a mask assembly which meets
the requirements of quick-donning for the wearer who may be faced
with hazardous flight conditions. The invention has the further
benefit of improved quick donning capability over eyewear, such as
glasses, being worn by the user. Since it is often the case that an
inflight emergency is followed by a fairly long period during which
the crewmembers must operate in the hazardous environment and guide
the aircraft to a safe landing, the mask of the present invention
is also configured to be comfortable when worn for extended periods
of time. Such a feature is particularly important in light of
certain regulations of some aviation regulatory bodies which
require that the mask be worn by one crewmember at all times. There
are also requirements by some regulatory bodies for usage of the
mask when a crewmember exits the flight deck. Other extended
operations scenarios may call for wearing the mask for three hours
or more and thus comfort of wear is highly desirable.
[0011] It is well recognized that the primary purpose of the
invention is to limit infiltration of pollutants and provide
adequate physiological oxygen volumes for the hazardous environment
resulting from either aircraft decompression or hazardous gases,
not limited to smoke, which may enter the crew compartment(s).
[0012] In a presently preferred embodiment, a feature of the
invention is the ability to provide an emergency breathing device
in which the flow of oxygen is adjustable according to
physiological requirements. Whether this feature is a requirement
is determined by the regulatory bodies having jurisdiction over the
regions in which the aircraft operates. It is also important that
the mask, once donned, leaves both hands of the wearer free to
perform his duties and that the mask provide the necessary field of
view to perform those functions. Accordingly, the invention is
designed to not only provide a wide field of view, but also provide
vented oxygen to purge the volume around the eyes and to prevent
condensation on the lens interior surfaces. Since part of the
crew's functions will inevitably include communication with other
crewmembers and ground controllers, the invention can also provide
an integrated microphone enabling continued communications between
aircraft crew and ground stations once the mask is worn.
[0013] In order to provide the above benefits, the present
invention utilizes a flexible lens instead of the rigid or
semi-rigid lens of prior art emergency crew masks, which, when
combined with a flexible material utilized in the balance of the
mask, allows the mask to be rolled up into a relatively small
package for stowage on a flight deck. It has been found that the
flexible lens of the present system, when combined with the
flexible face seal of the mask, provides improved benefits in the
ability to accommodate a wide variety of face and head sizes. The
invention also includes, in combination with the flexible lens and
flexible face seal, an inflatable harness, the inflation being
provided and controlled by an oxygen regulator which also provides
breathing oxygen to the wearer. A portion of the oxygen for
consumption by the wearer may also be distributed around the
wearer's eyes in order to purge and clear the lens in conditions
conducive to fogging and eye irritation.
[0014] In a presently preferred embodiment, the invention includes
a flexible elastomeric lens that is molded into a flexible face
seal surrounding the lens. The face seal includes mounting points
for an inflatable harness extending from the mask around the back
of the wearer's head. In this embodiment, the inflatable harness is
made of flexible elastomeric tubing surrounded by a flame resistant
covering of Nomex.RTM. or the like and includes connectors between
the inflatable tubing and the mask to keep the desired form and
shape of the harness when inflated. The connectors can include
adjustable straps to vary the size of the harness to fit a variety
of head sizes. The mask seal is molded to receive a regulator which
supplies oxygen or breathing gas to the wearer and also supplies
gas to the inflatable harness by a suitable passage. The mask can
also include passages from the regulator to the interior of the
lens to purge and clear the interior of the lens during wear. The
mask assembly may also be made by molding the entire mask of a
flexible optically transparent silicone or other suitable plastic
which can maintain optical quality in the lens region and has the
other features described above. The lens area of either embodiment
may be coated with an abrasion resistant material such as urethane
to prevent damage to the lens prior to and during use. In either
construction, a microphone can also be incorporated into the mask
to allow continued conversation between the crewmember and the
electronic communication system in the aircraft. Similarly,
provisions can be made in the mask to accommodate headsets or
earpieces for the crewmember, if required.
[0015] From the above it will be seen that the invention provides
an improved mask for use by aircraft flight crews during the event
of a depressurization or smoke in the cockpit, and also improves
the comfort level, visibility and storability of the mask, as well
as offering high performance with regard to isolation of the wearer
from the hostile environment. Other features and advantages of the
present invention will become apparent from the following detailed
description, taken in conjunction with the accompanying drawings,
which illustrate, by way of example, the principles of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of the crew mask of the present
invention, illustrating the general arrangement of the
components.
[0017] FIG. 2 is an illustration of the prior art mask and the
associated stowage volume for such a mask.
[0018] FIG. 3 is a perspective view of the mask of the present
invention illustrating the stowage volume for the mask of the
invention.
[0019] FIG. 4 is a vertical view of the prior art masks and their
relationship to the range of head sizes to be accommodated by the
mask.
[0020] FIG. 5 is a vertical view of the present invention mask
illustrating the ability of the mask to accommodate to the
appropriate range of head sizes.
[0021] FIG. 6 is a side view of the mask of the present invention
illustrating the sealing portions of the mask and their
relationship to the lens in the face of the wearer.
[0022] FIG. 7 is a vertical view of the mask illustrating the field
of view of the eyes of the wearer and the accommodation of the
field of view by the present invention and prior art lenses.
[0023] FIG. 8 is a perspective view of a first embodiment of the
inflatable mask harness.
[0024] FIG. 9 is a rear perspective view of a second embodiment of
the inflatable mask of the invention.
[0025] FIG. 10 is a rear perspective view of a third embodiment of
the inflatable harness of the present invention.
[0026] FIG. 11 is a rear perspective view of a fourth embodiment of
the inflatable harness of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0027] As shown in the exemplary drawings, a first presently
preferred embodiment of the present invention is embodied in a
flexible, full face coverage mask for use by aircraft flight crews
which includes a flexible lens sealingly molded in to the face
seal. The mask also incorporates an inflatable harness which is
inflated by the breathing oxygen regulated by a regulator
incorporated into the face mask. The mask also provides for purging
of the interior of the flexible lens by gas from the regulator in
order to retard fogging and other obscuration of the view out of
the lens by the wearer. The entire assembly is capable of being
rolled up into a relatively small package, which facilitates its
installation within the limited available space readily at hand to
the seated crewmember on the flight deck. In a second presently
preferred embodiment, the entire flexible mask portion, including
the lens, can be formed of a single unit, either through use of an
insert molded into the balance of the mask or by use of an
elastomeric transparent material for the entire face mask portion
of the assembly.
[0028] FIG. 1 illustrates a general arrangement of a first
preferred embodiment of the present invention. The mask assembly 10
includes a face seal molding 12 formed to fit around the periphery
of the face of the wearer and receive a flexible lens 14 which is
bonded or inserted into the elastomeric face seal 12. The lower
forward portion of the face seal 12 incorporates a portion which
includes an oxygen supply regulator assembly 16 removably attached
to the lower forward portion of the mask. The regulator 16 supplies
breathing oxygen to the mask wearer through ports internal to the
lower forward portion of the face seal 12, and also supplies oxygen
or other breathing gas mixtures to an inflatable harness 18
connected to the breathing gas regulator and the face seal 12 via
suitable gas passages and connectors in the mask. Connecting straps
20 and 22 are then similarly connected at their extremities to a
connector 24 which may also be adjustable to provide means to
adjust for the size and comfort of the mask once inflated. A
further connector 26 connects strap 20 to the inflatable portion 18
of the harness assembly.
[0029] In a presently preferred embodiment, a clear flexible
elastomeric lens 14 is either bonded or inserted into a receptacle
in the elastomeric face seal 12. The use of the flexible lens in
concert with the elastomeric face seal of the invention serves to
improve the ability of the mask to seal out toxic or vision
impairing gases. These improved face sealing characteristics also
improve the oxygen consumption performance of the mask, as there is
less leakage over a wider variety of face configurations. The
oxygen supply for the mask is provided by oxygen supply tube 28
connected to regulator 16. In order to facilitate communication,
the mask may also incorporate a microphone (not shown) which is
connected to the aircraft communication system by electrical wiring
30, which may be concurrently routed with oxygen supply tube
28.
[0030] Certain benefits of the present invention may be better
understood by reference to FIGS. 2 and 3, which illustrate the
difference in size and configuration of the present invention as
compared to prior art aircraft emergency crew masks incorporating
rigid lens assemblies. As illustrated in the prior art, FIG. 2, a
mask 32 incorporating a rigid lens assembly 34 of necessity
requires a fairly large enclosure 36 into which the mask must fit
to account for the inflexibility of the lens, regardless of the
flexibility of the balance of the mask assembly. In contrast, by
use of the flexible lens, flexible face seal and inflatable harness
of the present invention, as illustrated in FIG. 3, the mask may be
rolled so that lens 14 and face seal 12 consume a substantially
smaller volume 38 as compared to prior art masks. This feature of
the invention allows the mask to be mounted in a considerably
smaller space within the aircraft and possibly be placed more
conveniently to hand of the crewmember during times of emergency.
In light of the increased complexity and sophistication of modern
aircraft, and the use of fewer crewmembers compared to previous
equally complex aircraft, flight deck volume has been in short
supply and thus the smaller envelope of the stowed mask of the
present invention represents a substantial advantage over prior art
emergency crew masks.
[0031] Referring to FIGS. 4 and 5, FIG. 4 illustrates how the
present invention readily adapts to faces of various sizes more
easily than prior art masks. More specifically, referring to FIG.
4, which illustrates both large 40 and small 42 heads which may be
required to be accommodated by emergency flight crew masks
assemblies, it may be seen that a conventional rigid mask lens
assembly 34 incorporated into conventional mask face seal 44 cannot
accommodate this range of head sizes without highly compliant seals
provided at the edges of the lens and at the edges of the face
seal. Comparing the flexibility of the present lens assembly and
the face seal illustrated in phantom as 46 shows the relatively
small amount of flexibility available in a prior art lens assembly
to accommodate the range of head sizes desired. Referring to FIG.
5, it may be seen that the same head sizes 40 and 42 may be more
readily accommodated by the present invention. More specifically,
it can be seen that the flexible integrated mask and lens assembly
48 can deflect over a substantially greater range as illustrated in
phantom by dotted lines 50 to more easily accommodate the required
range of head sizes. Furthermore, such accommodation is
accomplished without the requirements for high compliance seals at
the edges of the lens assembly in order to bridge the difference in
rigidity between a rigid lens and a soft face seal, and the
stresses on the seal between the lens and the face seal are
substantially reduced by the increased flexibility of the lens of
the present invention. Because of the lens flexibility in the
present invention, the entire face seal can then flex more to
varying head and face sizes. Another benefit of the present
invention is that since the soft lens is intentionally flexed with
the face seal by the combination to the face of the user in
response to the inflatable harness, less face seal frame structure
is needed than in hard lens designs which must include an adequate
structure to support the rigid lens.
[0032] FIG. 6 is a cross sectional view of the flexible mask and
lens assembly of the present invention, illustrating the ease with
which the mask both accommodates to the face of the user and
provides a seal with the user's face. Referring to FIG. 6, which
illustrates a cross sectional view of the mask assembly of the
present invention on the face of the user, it can be seen that the
flexible face seal portion 12 conforms closely with the face of the
wearer 52, thereby providing an excellent seal for the mask for a
variety of face configurations and surfaces. Flexible lens 14 is
sealingly attached to face seal 12 at positions 54, 56, allowing
face seal 12 to conform closely to the wearer's face by deflecting
to accommodate any of a variety of facial configurations. A nose
bridge seal portion 58 is molded into the face seal 12 in order to
provide a particularly compliant configuration for sealing across
the nose bridge of the wearer.
[0033] FIG. 7 is an illustration of a vertical aspect illustrating
the field of view of a wearer, and showing the superior
accommodation of fields of view of a wearer by the present
invention. The wearer 60, whose eyeballs 62 are capable of a field
of view .theta. is ordinarily limited by the field of view of a
rigid lens of the type utilized in the prior art 64. Such a rigid
or semi-rigid lens, while providing good optical quality, does not
allow for a broad field of view and this may have certain important
limitations, particularly in the event of emergency circumstances
for a flight crew in an aircraft. By contrast, the present
invention lens 14 is capable of deflection over a far wider region
of the wearer's face while maintaining acceptable optical quality,
thus allowing for a full view through the optical portion of the
mask of the field of view .theta. of the user's eyes 62. This wide
field of view is further enhanced by the ability to provide a
closely fitting mask on the side portions of the face by use of the
flexible lens 14 and flexible face seal 12 which can conform
tightly with the forward side portions of the wearer's face.
[0034] FIGS. 8 through 11 illustrate a variety of configurations
which may be used for the inflatable harness in order to provide
close fitting and comfort for the wearer of the mask of the present
invention. The inflatable portion of FIG. 8 includes both a lateral
wrap-around elastomeric tube 66 and a central circular elastomeric
tube 68 which are connected to one another by a harness connection
70 and into the mask by adjustable straps 72. A similar
configuration is illustrated in FIG. 9, in which a single
inflatable tube 66 is configured to assume a similar shape to that
of FIG. 8 by connectors 74, thereby gaining the benefit of a single
continuous tube to be used for the inflatable harness assembly.
Similarly to FIG. 8 the inflatable portion of the harness is then
attached to the face seal by straps 72. FIG. 10 illustrates a
further variation in which the inflatable assembly consists of both
a top and bottom lateral tube 66, 76 connected by a vertical tube
80, all of which are supplied with air via the regulator in the
forward portion of the mask. FIG. 11 illustrates yet another
configuration for the harness which may be advantageously used with
the invention. In this embodiment elastomeric tubes 82, 84 are
attached to mask face seal 12 by connectors 86 and are held in
place in the crossed position behind the wearer's head by retainer
88. A strap 90 also serves to preserve the shape of the harness
during use.
[0035] It is important that the lens of the present system have
sufficient optical quality and resistance to abrasion and other
damage to function similarly to the rigid and semi-rigid lenses of
prior art masks. It is well known that a number of formulations of
silicone exist that provide resistances to yellowing and other
optical degradation sufficient for use in a mask which must be
stored for long periods of time prior to use. One such material
which should be suitable for this purpose as a lens material is
General Electric SE6800-D2 silicone in the "clear" peroxide cured
molding grade. Other clear, flexible plastic materials with optical
transmittance in the 80% range may also be suitable, depending on
the detail design of the mask. There are also scratch resistant
additives and coatings that are available for silicone formulations
which enhance the ability of the lens to maintain optical quality
when subject to abrasion. One such scratch resistant coating
involves the coating of the lens with urethane. In a presently
preferred embodiment, the invention involves the use of a urethane
coated silicone lens bonded to the silicone based face seal by use
of the following process. The lens is premolded out of silicone and
coated with an abrasion resistive coating, such as urethane. The
lens is then placed in a mold which is designed to receive the lens
and mold the liquid mask material around the lens and other
inserts, if any, such as the harness mounting hardware and
regulator mounting assembly. The lens perimeter and mask seal is
cleaned with Methyl Ethyl Ketone and the lens with Hexane. An
adhesive such as 34D manufactured by Synthetic Surfaces, Scotch
Plains, N.J. is then used to adhere the lens to the face seal. The
mask is then cured, depending upon the requirements of the
particular silicone, and the completed mask is removed from the
mold.
[0036] An important aspect of the invention is the ability to
combine the flexibility of the mask seal and lens with the
inflatable harness in order to provide previously unavailable
levels of lens field of view, storability, comfort, wearability and
sealing in a mask that is also providing sufficient optical quality
for use under high stress conditions by flight crews. While a
variety of regulators may be used, in a presently preferred
embodiment, one regulator suitable for use with the mask is the
Puritan-Bennett oxygen pressure regulator previously utilized in
the Puritan-Bennett Sweep On 2000 Crew Mask, available without a
lens but with an inflatable harness made of silicone tubing
overlaid with Nomex.RTM. braided material. This demand regulator
also provide the ability to adjust the pressure in the inflatable
harness, and thus the comfort of the harness, by access to a crew
control knob or lever on the side of the demand regulator assembly.
The demand regulator assembly also provides for a means to provide
purging air to the inside of the lens assembly via suitably
arranged passages in the mask.
[0037] A second presently preferred embodiment addresses the
desirable benefits, for cost, reliability and manufacturability
reasons, to manufacture the mask as a single piece lens and face
seal assembly out of transparent silicone of the type suitable for
use as a flexible lens material. It has been found that such a
configuration further simplifies the design of the mask by
eliminating the manufacturing step of sealing the lens with the
balance of the face seal, and avoiding irregularities in
flexibility associated with discontinuities between materials and
the transition between the lens and the face seal. Similarly to the
previously described embodiments, the forward lower portion of the
face seal is molded to accommodate the demand flow regulator and
the attach points of the inflatable harness straps to provide a
complete assembly. In this alternative method of construction, the
area of the mold representing the lens is finished to a
sufficiently high optical accuracy for the intended purpose and the
mold is configured to provide appropriate thickness to the lens
area in comparison to the balance of the mask. Then, an optical
quality clear silicone is used to mold the mask and to thus provide
an integrally formed mask and lens assembly. In a presently
preferred embodiment, a General Electric Silicone known as 454-3243
Ultra Tufel "Water Clear, Fast Cure can be used to mold such a mask
and provide acceptable clarity, flexibility, strengths and damage
resistance capabilities.
[0038] From the forgoing, it will be appreciated that the crew
emergency mask assembly of the present invention allows for a
substantially improved field of view and stowability while still
providing a comfortable and highly effective mask for use in
hazardous circumstances in the flight deck of a high performance
aircraft.
[0039] While several forms of the invention have been illustrated
and described, it will also be apparent that various modifications
can be made without departing from the spirit and scope of the
invention. Accordingly, it is not intended that the invention be
limited except as by the appended claims.
* * * * *