GB2441617A

GB2441617A - High G-force Breathing Mask

Info

Publication number: GB2441617A
Application number: GB0715302A
Authority: GB
Inventors: Joseph Anthony Griffiths
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-10-09
Filing date: 2003-10-09
Publication date: 2008-03-12
Anticipated expiration: 2023-10-09
Also published as: GB2441617B; GB0715302D0

Abstract

A breathing mask comprising a rigid shell 14 with a flexible annular sleeve 13 attached to the periphery of the shell and extending beyond the edge thereof. The flexible sleeve is adapted to make a seal with the pilot's face and the periphery of the flexible sleeve includes a cushion 15 having a skirt 18 projecting therefrom in a direction away from the pilot's face so that, in use, the skirt lies flush against the pilot's face to make an air-tight seal therewith. The cushion may be partially or completely filled with open cell foam 16.

Description

High G-Force Breathing Mask This invention relates to a breathing mask

and particularly but not exclusively for use by pilots who are subjected to high G forces.

Breathing equipment for aircrew normally comprises a flexible facemask having an inspiratory valve supplied with oxygen or some other breathable gas and an expiratory valve to allow the pilot to expel the air from the mask on exhalation.

The facemask is attached to the pilot's flying helmet by means of a harness incorporating a releasable fitting.

In fighter aircraft, it is essential that the facemask makes a seal with the pilot's face at all times. Under normal flying conditions, this is not a problem as the pilot adjusts the harness tension so that the mask makes the necessary seal with his face and is also comfortable to wear. The supply of the breathable mixture through the mask is controlled by a breathing gas regulator which is responsive to the G-forces that it is subjected to. In other words, when the G-force increases, the pressure of the gas supply to the interior of the mask is correspondingly increased and vice-versa. Thus, changes in the G-forces applied to the regulator controlling the breathable gas supply result in automatic changes in pressure in the interior of the mask. It will be appreciated that unless some means is provided to maintain the seal between the mask and the pilot's face, any substantial increase in pressure within the mask cavity can cause the mask seal to leak so that the pilot will not receive the pressure of breathable gas he requires and he could therefore black out or experience G-loc' (G-Ioss of consciousness).

Therefore, the construction and design of the sealing means itself is critical for the mask to make an air-tight seal against the pilot's face. Many prior art masks feature a rounded rubber cushion as the sealing means. These work adequately under normal flying conditions, but when the pressure in the mask is increased, the curved edge of the sealing means that contacts the pilot's face is inadequate to prevent the pressurised air from escaping from within the oro-nasal mask. Facial geometry varies from pilot to pilot, so it is desirable to design a mask and sealing means which are able to make a perfect air-tight seal under pressure on all pilots' faces, as providing custom made masks to fit the facial contours of each individual pilot It is therefore an object of the present invention to provide a mask that can maintain an airtight seal with a pilot's face when subject to forces of up to 9G, with an improved oro-nasal sealing means that substantially alleviates or overcomes the problems outlined above.

Accordingly, the present invention provides a breathing mask comprising a rigid shell with a flexible oro-nasal mask attached to the periphery of the shell and extending beyond the edge thereof, said flexible oro-nasal mask being adapted to make a seal with the pilot's face, the periphery of the flexible oro-nasal mask including a cushion having a skirt projecting therefrom in a direction away from the pilot's face so that, in use, the skirt lies flush against the pilot's face to make an air-tight seal therewith.

However, in a second embodiment of the present invention, there is provided a breathing mask comprising a rigid shell with a flexible annular sleeve attached to the periphery of the shell and extending beyond the edge thereof, said flexible sleeve being adapted to make a seal with the pilot's face, the periphery of the sleeve including a cushion having a skirt projecting therefrom in a direction away from the pilot's face so that, in use, the skirt lies flush against the pilot's face to make an air-tight seal therewith Preferably, the cushion is hollow and toroidal in shape and includes an air hole therein to allow gas pressure to balance between the interior and the exterior of the cushion. Alternatively the cushion is C-shaped in cross-section and forms an envelope.

In a preferred embodiment, the hollow interior of the cushion is partially filled with open cell foam. However, the hollow interior of the cushion may be completely filled with open cell foam.

A preferred embodiment of the present invention will now be described, by way of example only, with reference to the following drawings, in which: Figure 1 is a side view of a facemask of the invention in use with an aircrew helmet and breathable gas supply; Figure 2 is an enlarged side view of the facemask shown in Figure 1; Figure 3 is a cross-section view of the mask of Figures 1 and 2 along line X -X; Figure 4A is a schematic cross-section of a prior art facemask on a pilot's face when breathable gas under high pressure has been applied thereto; and Figure 4B is a schematic cross-section of the facemask of Figures 1 to 3 on a pilot's face when breathable gas under high pressure has been applied thereto.

Referring now to the drawings, Figure 1 shows a pilot I wearing a rigid protective helmet 2. A flexible oro-nasal mask 3, usually made of a natural or synthetic rubber material, surrounds the pilot's nose and mouth and is mounted in a rigid shell 14 attached to the helmet 2 by means of harness arrangement 5 which includes adjustable means (not shown) so that its length can be readily altered to ensure that the oro-nasal mask 3 rests comfortably on the pilot's face with its peripheral edge 20 making a proper seal with the area of the pilot's face surrounding the nose and mouth. It should be noted that the harness 5 is made of an inextensible material such as webbing or a metal wire secured at mounting point P to the rigid shell 14 and at its opposite end in mounting 7. Thus, when the shell 14 and mask 3 are in position on the pilot's face, the position of the rigid shell 14 relative to the helmet 2 cannot change and it remains at a fixed distance therefrom.

A breathable gas such as oxygen is supplied to the interior of the mask 3 from an oxygen regulator 9 through hose 8.

Inspiratory and expiratory valves (not shown) are provided in the mask 3 in known manner.

Figures 2 and 3 show the present invention in more detail which comprises the rigid shell 14 with a flexible annular sleeve 13 made from a natural or synthetic rubber to surround a pilot's nose and mouth and which is bonded at 13A to the inner peripheral edge surface of the shell 14. The flexible sleeve 13 and rigid shell 14 are adapted to be fitted to a helmet of the pilot as hereinbefore described. The peripheral edge 20 of the flexible sleeve 13 that contacts and makes a seal with the pilot's face comprises a cushion 15 having a hollow core which is partially filled with an open cell foam 16, leaving the remaining space as an air gap 17. A vent hole 19 is provided in the cushion 15 which is in fluid communication with the air-gap 17 inside the cushion. A skirt 18 extends inwardly substantially tangentially from the edge of the cushion 15 around its entire perimeter. The skirt 18 has an inner surface 18A and an outer surface 18B.

In use, the mask is attached to the pilot's helmet as shown in Figure 1. The peripheral edge 20 of the cushion 15 contacts the pilot's face and surrounds his nose and mouth. In use the outer surface 18B of the skirt 18 presses against the pilot's face and makes a seal therewith.

The difference between this arrangement and prior art facemask seals can be seen in Figures 4A and 4B. The seal in Figure 4A is rounded and presents a curved edge 21 leading to a contact point 22 on the pilot's face. This arrangement is such that when breathable gas at high pressure is supplied to the interior of the mask, it tends to push the edge 21 away from the pilot's face and escapes outside the mask as shown by the arrows. As mentioned above, this loss of breathable gas pressure can be very dangerous during high-G manoeuvres and can lead to G-loc'. In contrast, the mask of the invention is shown in Figure 4B, and it can be seen that the skirt 18 extends inwardly from the cushion 15 and the outer surface 1 8B of said skirt 18 lies against the pilot's face. Unlike the seal of the prior art masks described above, this configuration does not present a curved edge leading to the point of contact on the pilot's face. Thus, when high pressure breathable gas is supplied to the interior of the mask, the gas pressure exerts a force on the inner surface 18A of the skirt 18, as illustrated by the arrows F' in Figure 4B and pushes the skirt 18 into tighter contact with the pilot's face, to strengthen the air-tight seal therewith. It will be appreciated therefore that increasing the pressure of gas supplied to the interior of the mask increases the integrity of the seal, rather than weakening it as in the prior art.

The function of the vent hole 19 is to allow the pressure of the gas in the air gap 17 to equalise with the ambient pressure in the cockpit as the plane changes altitude, to prevent damage occurring to the cushion 15.

For the avoidance of doubt, the flexible breathing masks can comprise either a flexible annular sleeve 13 bonded to the inner peripheral edge surface of the rigid shell 14 as illustrated in Figures 3 and 4B, or alternatively, may comprise a flexible oro-nasal mask in the form of shell contained within the rigid shell 14. Both embodiments of the invention are intended to fall within the scope of the claims.

In addition, although the embodiment shown includes foam in the hollow of the cushion, the invention could also comprise the hollow cushion without foam therein

Claims

Claims 1. A breathing mask comprising a rigid shell with a flexible

oro-nasal mask attached to the periphery of the shell and extending beyond the edge thereof, said flexible oro-nasal mask being adapted to make a seal with the pilot's face, the periphery of the flexible oro-nasal mask including a cushion having a skirt projecting therefrom in a direction away from the pilot's face so that, in use, the skirt lies flush against the pilot's face to make an aix-tight seal therewith.
2. A mask according to claim 1, wherein the cushion is hollow and toroidal in shape and includes an air hole therein to allow gas pressure to balance between the interior and the exterior of the cushion.
3. A mask according to claim I wherein the cushion is C-shaped in cross-section and forms an envelope.
4. A mask according to claim 2 or claim 3 wherein the hollow interior of the cushion is partially filled with open cell foam.
5. A mask according to claim 2 or claim 3 wherein the hollow interior of the cushion is completely filled with open cell foam.
6. A breathing mask comprising a rigid shell with a flexible annular sleeve attached to the periphery of the shell and extending beyond the edge thereof, said flexible sleeve being adapted to make a seal with the pilot's face, the periphery of the sleeve including a cushion having a skirt projecting therefrom in a direction away from the pilot's face so that, in use, the skirt lies flush against the pilot's face to make an air-tight seal therewith.
7. A mask according to claim 6 wherein the cushion is hollow and toroidal in shape and includes an air hole therein to allow gas pressure to balance between the interior and the exterior of the cushion.
8. A mask according to claim 6 wherein the cushion is C-shaped in cross-section and forms an envelope.
9. A mask according to claim 7 or claim 8 wherein the hollow interior of the cushion is partially filled with open cell foam.
10. A mask according to claim 7 or claim 8 wherein the hollow interior of the cushion is completely filled with open cell foam.

io
ii. A mask substantially as hereinbefore described with reference to the accompanying drawings.