GB2393662A

GB2393662A - Mask mounting system with annular strap

Info

Publication number: GB2393662A
Application number: GB0302191A
Authority: GB
Inventors: Joseph Anthony Griffiths
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-10-03
Filing date: 2003-01-30
Publication date: 2004-04-07
Also published as: GB0222940D0; GB0302191D0

Abstract

Aircrew oxygen mask mounting system for attaching a flexible oro-nasal mask (3) mounted in a rigid shell (4) to a pilot's helmet (2A) at a fixed distance therefrom. The periphery (10) of the mask (3) is adapted to make a seal with the pilot's face. The rigid shell (4) is preferably attached to an annular steel band (15) which mounts said shell on the pilot's flying helmet at a fixed distance therefrom. Extendable means (13 Fig 2) associated with the facemask (3) automatically move the mask relative to the rigid shell (4) and the pilot's face to vary the seal therewith when breathable gas at a pressure above that required for normal breathing supplied to the interior of the mask. The annular band (15) is dimensioned to pass around the rear of the wearer's head and has means (21) thereon for releasably attaching it to the pilot's helmet. The annular band (15) can have a removable front portion on which the rigid shell (4) and mask (3) are mounted.

Description

1 2393662

Aircrew Oxygen Mask Mounting System This invention relates to means for mounting an oxygen mask on a pilot's flying helmet.

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 lo flying helmet by means of a harness incorporating a releasable fitting.

In fighter aircraft, it is essential that the facemask makes a proper 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 Is 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 mask is correspondingly increased and vice o 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 suitable 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 25 cause the mask seal to leak so that the pilot will not receive the pressure of breathable gas he requires and could black out.

- 2 One known way of overcoming this problem has been to include an overcentre toggle in the harness assembly attaching the mask to the pilot's head. This toggle is in a low tensioned position for normal flight but, when the pilot knows in advance that he will require pressurised 5 breathing, for instance when pulling G or in emergency conditions, he moves the toggle into its tensioned position which draws the facemask more tightly against his face thereby hopefully improving its seal therewith. Once this need has passed, he then releases the toggle.

Indeed, he wants to do this as soon as possible because the pressure lo exerted on his face when the toggle is engaged is so great that it makes the mask very uncomfortable to wear over long periods of time.

In order to overcome these problems, the facemask disclosed in European Patent No. 0541549 was developed and a breathing apparatus Is was provided in which the oro-nasal mask was mounted in a rigid shell attached to the pilot's helmet at a fixed distance therefrom, the oro- nasal mask Including extendable means operable to cause the oro-nasal mask or a portion thereof to move automatically relative to the pilot's face to vary the seal therewith dependent on the breathable gas pressure 20 supplied to the mask.

In one embodiment, the extensible means is an inflatable bladder located between the oro-nasal mask and the rigid shell. In another embodiment, the extensible means is located in the wall of the oro-nasal mask and as comprises a series of folds or bellows. In both embodiments, when breathable gas at a pressure above that needed for normal breathing is supplied to the bladder or the interior of the oro-nasal mask, the bladder inflates or the bellows or folds extend to move the mask relative to the

- 3 rigid shell in which it is mounted and thereby automatically vary the pressure of the mask on the pilot's face and its seal therewith dependent on the pressure of the breathable gas supplied to it. The essence of this solution is that the position of the rigid shell in which the dynamically s movable oro-nasal mask is mounted is held and maintained at a fixed distance from the pilot's face and helmet so that the mask can be made to move relative to this fixed shell and therefore relative to the pilot's face. lo This solution overcame all the problems of the prior art systems as it

automatically pressed the oro-nasal facemask into tighter contact with the wearer's face as the G-forces generated during the turn increased, the pressure on the pilot's face reducing automatically as the turn was completed and the G-forces reduced. However, modern fighter aircraft Is can now generate up to 9G in a turn so the pressure of breathable gas supplied to the interior of the mask has to be substantially increased if he is to be able to breath satisfactorily and not black out during the turn due to a lack of oxygen supplied to the brain. Thus, any breathing system that he uses must ensure that the periphery of the oro-nasal mask 20 makes and maintains a seal with his face at all times otherwise the breathable gas at high pressure supplied to the interior of the mask will leak out at its edge seal and he will not receive the required amount of high pressure gas needed to keep him conscious. The seal can also be affected if the mask pivots relative to the wearer's face. For instance, at as very high G-forces, the pilot's lower jaw can move and thus the edge seal of the facemask in contact therewith can be disrupted and it can then leak.

- 4 In the prior art system just discussed, the oro-nasal mask is attached to a

rigid flying helmet. The role of the flying helmet has changed in recent years and is now required to do much more than simply protect the wearer's head in an impact. More commonly, it is used to mount s avionics such as night vision goggles (NVG). Different avionics may be required for different combat missions so a different helmet and associated avionics can be necessary for each different type of mission that a pilot may carry out. Thus, a pilot may need several different types of helmet to provide him with all the equipment that he needs for his lo various combat missions. Obviously producing individual helmets for each type of combat mission was very expensive so pilots now wear a two-part helmet which comprises a rigid outer shell (on which the avionics can be mounted) which fits over and is mounted on a lightweight inner support which includes all the pilot's specific functions Is such as his ear cups and communications etc. Thus, the outer helmet can be made role specific whereas the inner support will be man specific.

A pilot therefore needs only one inner support specifically adapted to fit him to which various different outer mission specific helmets can be fitted. The oxygen breathing system of the present invention however to needs to be fitted to these two-part helmets and this creates a different set of problems.

As already explained, it is an essential feature of the breathing system of the present invention that the rigid outer shell in which the oronasal as mask is mounted has to be maintained at a fixed distance from the pilot's helmet. When the fixed length strap is fitted to the lightweight inner helmet of a dual helmet, if the pilot makes a high G turn, the dynamic movement of the oro-nasal mask relative to the fixed shell which is

- 5 ( created by the inflation of the extensible means in the oro-nasal mask can cause the sides of the inner helmet to which the strap is attached to flex inwardly. This inward flexing dilutes the amount of movement that the oro-nasal mask can make towards the wearer's face so a lesser s pressure is applied thereto and the edge seal of the mask can leak which could prove fatal.

It is an object of the invention therefore to provide means for releasably attaching an oxygen mask on a helmet, particularly the flexible inner lo support of a two-part helmet, which overcomes or substantially reduces these problems.

According to the invention, there is provided mask mounting means for attaching a flexible oro-nasal mask mounted in a rigid shell to a pilot's Is helmet at a fixed distance therefrom, the flexible oro-nasal mask having a periphery adapted to make a seal with the pilot's face, the flexible mask including extendable means associated with the facemask operable to automatically move the mask relative to the rigid shell and the pilot's face to vary the seal therewith when breathable gas at a pressure above to that required for normal breathing is supplied to the interior of the mask, the mask mounting means comprising an annular nonextendable member on which the rigid shell is mounted, said annular member being dimensioned to pass around the rear of the wearer's head and having attachment means thereon for securing said annular member to the 25 pilot's helmet.

In one embodiment, the annular member is a steel band and the oro-

nasal mask is attached to the front of said band.

- 6 The annular member can include adjusting means whereby the circumference thereof can be changed to improve the fit of the mask from the pilot's face.

s Conveniently, the front portion of the annular member on which the oronasal mask is mounted includes means to allow said front portion to be detachable from the remainder of the annular member.

lo In the preferred embodiment, the rear portion of the annular member is permanently attached to the pilot's helmet and the front portion thereof includes connection means for releasably securing said front portion to said rear portion.

Is Preferably the attachment means attach the annular member to the interior of the helmet.

In an alternative embodiment, the front portion of the annular member comprises a rigid cross member to which the rigid shell housing the to flexible oro-nasal mask is attached, said cross member being connected to the remainder of the annular member by a pair of fixed length straps or wires attached to the opposite ends of said cross member, each strap or wire having connector means at its end remote from the cross member to releasably attach it to the remainder of the annular member 2s secured to the pilot's helmet.

Conveniently, the front portion of the annular member is semi-circular and the rigid shell and flexible oro-nasal mask are attached to the front

- 7 central portion thereof, each opposite end of said semi-circular band having connectors therein to releasably connect the front portion of the annular member to the remainder thereof.

s According to another aspect of the invention, there is provided mask mounting means for releasably attaching a flexible oro-nasal mask mounted in a rigid shell to a pilot's helmet at a fixed distance therefrom, the mask being connectable to the helmet by attachment means having opposite ends which are received in receiving means on the helmet, the 10 mask mounting means comprising a non-extendable rigid member having a portion which, in use, extends around the rear of the pilot's head, said rigid member being immovably attachable to the helmet and including receiving means to receive and anchor the face mask attachment means thereto.

Preferably the rigid member is a metal band.

In one embodiment, the rigid member is semi-circular and the receiving means are located at the opposite ends thereof. However, it could be 20 annular with the mask attached to a front portion thereof which may itself be releasably attached to the remainder.

Preferably, the rigid member is attached to the interior of the pilot's helmet. According to a still further aspect of the invention, there is provided a two-part flying helmet comprising a flexible inner support on which a rigid outer shell is mounted, the flexible inner support having a non

- 8 extendible rigid member secured thereto with a portion thereof extending around the rear of the inner support, said rigid member having mounting means thereon located on opposite sides of the flexible inner support to receive and anchor breathing equipment to the helmet.

s In a preferred embodiment, the rigid member is semi-circular and attached to the interior of the inner support.

A preferred embodiment of the invention will now be described, by way lo of example only, with reference to the accompanying drawings, in which: Figure 1 shows a prior art breathing system with a flexible oro-nasal

mask mounted in a rigid shell; Figure 2 is a schematic view, on an enlarged scale, of the oro-nasal Is facemask and rigid shell shown in Figure 1; Figure 3 is a schematic plan view showing what happens if the prior art

facemask of Figures 1 and 2 is mounted on the flexible inner helmet of a pilot's two-part helmet; Figure 4 is a perspective view of one form of improved helmet mounting 20 system which overcomes the problems of the prior art system shown in

Figure 3; Figure 5 is a perspective view of another form of helmet mounting system of the invention; and Figure 6 is a plan view of the helmet mounting system shown in Figure 25 4. Referring now to the drawings, Figure 1 shows a pilot 1 wearing a rigid protective helmet 2. A flexible oro-nasal facemask 3, usually made of a

( 9 natural synthetic rubber, surrounds the pilot's nose and mouth and is mounted in a rigid plastic shell 4 attached to the helmet 2 by means of a harness arrangement 5 having a fitting 6 at one end to releasably attach it to a fitting part 7 mounted on the helmet. The harness 5 includes s adjustable means (not shown) so that its length can readily be adjusted to ensure that the facemask 3 rests comfortably on the pilot's face with its edge lip 10 making a proper seal with the area of the pilot's face surrounding his nose and mouth. An avionic armament sight 11 is mounted upon an arm 12 attached to the helmet 2 and protrudes lo forwardly therefrom into the pilot's line of vision as illustrated. The harness or strap 5 is inextendable which means that the rigid shell 4 is mounted at a fixed distance from the helmet 2.

Breathable gas such as oxygen is supplied to the interior of the facemask Is 3 from pressurised gas supply 9 controlled by a regulator (not shown).

As can be seen more clearly in Figure 2, the wall of the facemask 3 includes extendable means 13 housed within the rigid shell 4. The purpose of the extendable means 13 is to enable the edge seal 10 to move in a direction generally parallel to the wall of the rigid shell 4 when to the pressure supplied to the interior of the facemask 3 is increased as a result of the regulator (not shown) being activated when the aircraft makes a turn. When the pressure supplied to the interior of the facemask 3 increases during the turn, the wall thereof expands to cope with the increased pressure. As the wall cannot move radially outwardly as because it is contained within the rigid shell 4, it can only move in a direction generally towards the plot's face in the direction of the arrows and thereby improves its seal therewith.

- 10 Turning now to the arrangement shown in Figure 3, this illustrates what would happen if the prior art breathing system shown in Figures 1 and 2

is mounted on the flexible inner helmet of a two-part helmet. It can be seen that the rigid shell 4 in which the oro-nasal mask 3 is mounted is s attached by means of the fixed length strap 5 to inner helmet part 2A in much the same way as illustrated in Figure 1. It should be noted that the inner helmet 2A has to be spaced from the pilot's head by distance A to accommodate ear cups 14. This has the effect of increasing the angle X of the straps 5 relative to the wearer's face. Because the straps or wires lo 5 are attached to the outside of the rigid shell 2A in the temple region, this only further increases the angle X. In order to obtain the maximum amount of linear movement directly towards and away from the wearer's face in the direction of arrow F. the angle X needs to be as small as possible. If the angle X is substantial as illustrated, when the pressurised Is breathable gas is supplied to the interior of the oro- nasal mask 3, movement of the mask towards and away from the pilot's face in the direction of arrow F tends to draw helmet portions 2B inwardly towards the pilot's cheeks in the region where the fixed length straps 5 are mounted as indicated by the dotted lines P. This has the effect of 20 diluting the amount of axial movement of the mask 3 in the direction of arrow F relative to the pilot's face and thus the seal it makes with his face is not as good as it should be so it will leak. This could prove fatal in the combat situation because the pilot will not receive the required quantity of high pressure breathable gas he needs to prevent him from 25 blacking out.

Referring now to Figure 4, there is shown a mask mounting system of the present invention which overcomes the problems discussed in

- 11 relation to the prior art system just described with reference to Figures 1

to 3. It can be seen that instead of mounting the rigid shell 4 with the flexible oro-nasal mask 3 therein on the helmet 2A by means of two separate fixed length straps 5, an annular rigid band 15, preferably made s of steel or some other lightweight rigid material such as carbon fibre, is secured to the inner surface of a regular helmet or lightweight inner helmet 2A of a two-part helmet (the heavier rigid outer helmet is not illustrated). The annular band 15 has a front portion 1 SA on which the rigid shell 4 is fixedly mounted by means 16, the flexible oro-nasal mask lo 3 being mounted therein in the conventional way. The annular band 15 has a rear portion 1 5B which extends around the rear of the helmet 2A and is fixedly secured to the inner surface of portions 2B of the helmet 2A by securing means 17 of known type.

Is The front portion 15A of the annular band can include known fine adjustment means 18 by means of which the pilot can adjust the fit of the flexible mask 3 on his face. This can be a pawl and ratchet system which, once set, can only be released on demand.

20 The front portion 1 5A of the annular band 15 can include a quick release mechanism of known type so that the pilot can quickly remove the facemask 3 from his face in an emergency situation.

The advantage of the mask mounting system of the invention shown in 25 Figure 4 is that any load applied to the oro-nasal mask 3 in the direction of arrow F to move it towards the pilot's face and improve the edge seal therewith is transmitted along the annular band 15 and around the rear of the wearer's head. Thus, any inward flexing of the cheek portions 2B

- 12 of the helmet 2A are kept to a minimum and the linear movement of the mask 3 relative to the pilot's face is not diluted so an excellent seal can be maintained at all times and particularly during high speed turns generating high G-forces.

Referring now to Figures 5 and 6, there is shown the improved helmet mounting means of the present invention which overcomes the problems just discussed in relation to the use of the prior art system shown in

Figures 1-3 when mounted on a flexible inner helmet 2A of a two-part lo helmet.

It can be seen that a semi-circular rigid band 20, preferably made of metal but it could be made of any lightweight material such as carbon fibre, is mounted on the inside of the flexible inner helmet 2A of a two s part helmet (only the inner part 2Ais shown). The band 20 is secured to the helmet by rivets 21 or in any other convenient way so that it cannot move relative thereto. The band 20 has a rear portion 20A which is located behind the wearer's head at the rear of the helmet and an inwardly directed flange 22 with a hole 23 therein at its front ends, the to flanges 22 extending inwardly of the helmet sides 2B and terminates closely adjacent the pilot's cheeks. The connectors 6 releasably engage with holes 23 in the flanges 22 in known manner.

Rigid shell 4 in which the flexible oro-nasal mask 3 is mounted has a Is rigid cross member e.g. metal bar 15 attached to the front thereof by securing means 16. A pair of inextendable wires 5 each having a connector 6 thereon are attached to the bar 15 at each end 17 and 18 thereof. Each wire 5 can also include known fine adjustment means (not

- 13 shown) to allow the pilot to adjust the fit of the flexible mask 3 on his face. This can be a pawl and ratchet system which, once set, can be released on demand. It will be appreciated that the combination of the bar 15, wires 5 and semi-circular band 20 together form an annulus. l It will be noted from Figure 6 that angle "X" has been substantially reduced over that shown in Figure 3. Thus, in use, the mask 3 is moved towards the pilot's face in the direction of arrow F when pressurised breathable gas is supplied to the interior thereof, force F being lo transmitted around the annulus, namely along the wires 5 and around the band portion 20A behind the wearer's head. Because of the small angle X and the rigidity of the helmet 2A, the flexible cheek portions 2B of the helmet do not move inwardly towards the pilot's cheeks as indicated by the dotted lines in Figure 3 so the seal of the mask B makes Is with his face is not diluted and it can be maintained at all times, particularly when the aircraft is subjected to high G-forces.

Claims

- 14 Claims

1. Mask mounting means for attaching a flexible oro-nasal mask s mounted in a rigid shell to a pilot's helmet at a fixed distance therefrom, the flexible oro-nasal mask having a periphery adapted to make a seal with the pilot's face, and including extendable means operable to automatically move the mask relative to the rigid shell and the pilot's face to vary the seal therewith when breathable gas at a pressure above lo that required for normal breathing supplied to the interior of the mask characterized in that the mask mounting means comprises an annular non-extendable member on which the rigid shell is mounted, said annular member being dimensioned to pass around the rear of the wearer's head and having attachment means thereon for securing said Is annular member to the pilot's helmet.

2. Mask mounting means as claimed in claim 1 wherein the annular member is a steel band.

20

3. Mask mounting means as claimed in claim 2 wherein the oro-nasal mask is attached to the front of said band.

4. Mask mounting means as claimed in any preceding claim wherein the annular member includes adjusting means whereby the circumference 25 thereof can be changed to improve the fit of the mask on the pilot's face.

- 15

5. Mask mounting means as claimed in any preceding claim wherein the front portion of the annular member on which the oro-nasal mask is mounted is detachable from the remainder of the annular member.

s

6. Mask mounting means as claimed in claim 5 wherein the rear portion of the annular member is permanently attached to the pilot's helmet and the front portion includes connection means for releasably attaching the said front portion to said rear portion.

lo

7. Mask mounting means as claimed in any preceding claim wherein the attachment means for releasably securing the annular member to the pilot's helmet are operable to attach said member to the interior of the helmet. Is

8. Mask mounting means as claimed in any of claims 5-7 wherein the front portion of the annular member comprises a rigid cross member to which the rigid shell housing the flexible oro-nasal mask is attached, said cross member being connected to the remainder of the annular member by a pair of fixed length straps or wires each attached to an opposite end 20 of said cross member, each strap or wire having connector means at its end remote from the cross member to releasably attach the wire to the remainder of the annular member secured to the pilot's helmet.

9. Mask mounting means as claimed in any of claims 5-7 wherein the 25 front portion of the annular member is semi-circular and the rigid shell and flexible oro-nasal mask are attached to the front central portion thereof, each opposite end of said semi-circular band having a connector

- 16 thereon to releasably connect the front portion of the annular member to the remainder thereof.

10. Mask mounting means for releasably attaching a flexible oro-nasal s mask mounted in a rigid shell to a pilot's helmet at a fixed distance therefrom, the mask being connectable to the helmet by attachment means having opposite ends which are received in receiving means on the helmet characterized in that the mask mounting means comprises a non-extendable rigid member having a portion which, in use, extends lo around the rear of the pilots head, said rigid member being immovably attachable to the helmet and including receiving means to receive and anchor the facemask attachment means thereto.

11. Mask mounting means as claimed in claim 10 wherein the rigid Is member is a metal band.

12. Mask mounting means as claimed in claim 10 wherein the rigid member is semi-circular and the receiving means are located at the opposite ends thereof.

13. Mask mounting means as claimed in claim 10 or claim 11 wherein the rigid band is annular and the oro-nasal mask is attached to a front portion of said band.

14. Mask mounting means as claimed in claim 13 wherein the front portion of the rigid band is releasably attached to the remainder thereof.

- 17 (

15. Mask mounting means as claimed in any preceding claim wherein the rigid member is attachable to the interior of the pilot's helmet.

16. A two-part flying helmet comprising a flexible inner support on s which a rigid outer shell is mounted, the flexible inner support having a non-extendable rigid member secured thereto with a portion thereof extending around the rear of the inner support, said rigid member having mounting means thereon located on opposite sides of the flexible inner support to receive and anchor breathing equipment to the helmet.

17. A two-part helmet as claimed in claim 16 wherein the rigid member is semi-circular.

18. A two-part helmet as claimed in claim 17 wherein the semi-circular Is rigid member is secured to the interior of the inner support.

19. A two-part helmet as claimed in any of claims 16-18 wherein the rigid member is riveted to the inner support.

20

20. A two-part helmet as claimed in any of claims 16-19 wherein the breathing equipment is mounted on another rigid member which is releasably attached to the rigid member on the pilot's helmet, said two rigid members, when connected, forming a rigid annular support for the breathing equipment which maintains said equipment at a fixed distance 25 from the wearer's helmet.