WO1994001178A1

WO1994001178A1 - An oxygen supply system

Info

Publication number: WO1994001178A1
Application number: PCT/GB1993/001390
Authority: WO
Inventors: Robert James Mcfarlane; Allan David Cunningham
Original assignee: Gec-Marconi Avionics (Holdings) Ltd.
Priority date: 1992-07-11
Filing date: 1993-07-01
Publication date: 1994-01-20
Also published as: GB2268388A; GB9214782D0

Abstract

An oxygen supply system of the type commonly used by combat aircrew comprises a bladder (6) which is inflated by an oxygen supply to a face mask (1), and a tension strap (4) pulling the face mask (1) into firmer contact when oxygen is supplied. The bladder (6) exerts a force against the nape of the wearer such that a hard outer shell portion of a protective helmet which may extend over the region of the bladder is not displaced by inflation of the bladder.

Description

AN OXYGEN SUPPLY SYSTEM

This invention relates to an oxygen supply system and in particular, but not

exclusively, to an oxygen supply system for aircrew members.

It is necessary for all aircraft flying at relatively high altitudes to have available an oxygen supply for people on those aircraft. In commercial airliners this facility is provided by a mask which is normally made available on the possibility of oxygen being required, for example on decompression of the aircraft. The mask is worn only for the period during which oxygen is required, being retained in position by a piece of elastic or other similar material which extends around the head of the wearer. In combat aircraft it is desirable that an oxygen supply mask be worn for long periods, even though oxygen will not always be supplied, the mask often incorporating a microphone for communications. However prolonged wearing of such masks is often uncomfortable due to the force required in order to hold the mask sufficiently firmly on the face of the wearer in order to prevent the pressurized oxygen supply escaping by breaking the seal between the mask and the face of the wearer.

To overcome the above stated problems it has previously been proposed to provide a mask for combat aircrew which incorporates an inflatable seal around the lip of the mask such that the oxygen supply pressurizes and thereby expands the seal only when oxygen is supplied to the mask, thereby forcing the seal into firmer contact with the face. This enables the force applied to the mask to be reduced when oxygen is not supplied, but unfortunately the problem with such a system is that there is a reaction force on the helmet to which the mask is attached, which changes the

orientation of the helmet relative to the wearer. This is a problem when optical

components aligned with the eye of the wearer are mounted on the helmet. This same problem is also experienced in an alternative previously proposed arrangement wherein straps between the mask and helmet are tensioned by inflation of a bladder within the helmet which is also connected to the oxygen supply.

According to the present invention there is provided an oxygen supply system comprising: a face mask adapted to be connected to an oxygen supply for supplying oxygen to a wearer of the mask; an inflatable bladder also adapted to be connected to the oxygen supply for the mask; and at least one strap connecting the bladder to the mask, the at least one strap being arranged so that the mask and bladder can respectively be positioned on the face, and placed against the nape, of the wearer such that the supply of oxygen to the mask causes inflation of the bladder thereby holding the mask more firmly against the face of the wearer whilst oxygen is supplied.

By employing the present invention the tension on the strap or straps securing the mask to the face of the wearer is increased only when oxygen is supplied to the mask, making the mask more comfortable to wear at other times. The system is particularly advantageous when it further comprises a helmet having a rigid outer shell,

the helmet having an internal recess in the region of the bladder to permit inflation of the bladder without exertion of any forces on the outer shell. This prevents any adjustment of the position of the helmet on the head of the wearer caused by inflation of the bladder, or the consequent tensioning of the straps, and is particulariy advantageous when the helmet is adapted to provide a mounting for optical

components which are to be aligned with the head of the wearer.

According to one aspect of the invention, the at least one strap of the oxygen supply system is integral with an inner portion of the helmet, the inner portion comprising releasable anchoring points for the outer shell such that the bladder and inner portion of the helmet can be securely affixed to the head of the wearer prior to the outer shell being affixed to the anchoring points. This enables the bladder to be incorporated as part of the helmet while still ensuring that the bladder does not exert a force on the outer shell of the helmet. Alternatively the bladder can be retained in the recess, making removal and storage when not in use easier.

One embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings of which:

Figure 1 illustrates an oxygen supply system in accordance with the present invention, including an inner portion of a helmet;

Figure 2 illustrates a hard outer shell portion of the helmet which affixes to the inner portion illustrated in Figure 1 ; and Figure 3 is a schematic cross-section through the outer shell of Figure 2, and

shows its relationship to the head of a wearer of the helmet.

Referring to Figure 1 , there is illustrated an oxygen supply system comprising face mask 1 incorporating a microphone 2 and oxygen feed pipe 3 connected to an oxygen supply not shown. The mask is retained in position by strap 4 which extends

around an inflatable bladder 6 sandwiched between the strap 4 and the nape of the wearer. The bladder 6 is connected by pipe 7 to the same oxygen supply as the face mask, the bladder inflating upon supply of oxygen to the mask 1 , tensioning strap 4 pulling the mask into firmer contact with the face. Furthermore, because the strap 4 runs along the face of the wearer, when tensioned it pulls the side of the mask into the face, further assisting sealing.

The oxygen supply system also includes a helmet, the inner portion of which is also seen in Figure 1 and comprises a cap portion 8, ear buns 9 and chin strap 10. In use, the wearer of the oxygen supply system would don the inner helmet portion and locate the bladder 6 as shown, the mask itself being releasable by means of clip

11. Over these would then be mounted a rigid outer shell 20, illustrated in Figure 2, which is retained in position by means of engagement slots 21 co-operating with retaining pins 12 located on ear buns 9 of Figure 1.

The outer shell 20 of Figure 2 comprises mounting points 22 for optical components which are to be maintained in fixed position relative to the eyes of the wearer. The outer shell is therefore shaped, as can be seen from the cross-section of Figure 3, to provide a recess 30 to accommodate the bladder 6. The outer shell is therefore retained in position only by the strap/ear bun arrangement, 8, 9, 10 of

Figure 1 and internal foam padding 31. It is therefore isolated from any movement of the mask 1 or bladder 6.

The above is a description of one particular implementation of the invention. However it will be realised that various modifications can be made to the apparatus illustrated which will still be within the scope of the invention. In particular, numerous arrangements of mounting points between the inner portion of a helmet and the outer shell exist. Also, the bladder 6 and strap 4 could be retained in the recess 30 of the outer shell 20, regardless of whether the inner portion of the helmet is separable from the outer shell, provided the means of attachment is such that the forces exerted on the bladder by inflation press against the nape of the wearer and do not exert a force on the outer shell 20.

Claims

1. An oxygen supply system comprising: a face mask adapted to be connected to an oxygen supply for supplying oxygen to a wearer of the mask; an inflatable bladder also adapted to be connected to the oxygen supply for the mask; and at least

one strap connecting the bladder to the mask, the at least one strap being arranged so that the mask and bladder can respectively be positioned on the face, and placed against the nape, of the wearer such that the supply of oxygen to the mask causes inflation of the bladder thereby holding the mask more firmly against the face of the wearer whilst oxygen is supplied.

2. An oxygen supply system as claimed in claim 1 further comprising a helmet having a rigid outer shell, the helmet having an internal recess in the region of the bladder to permit inflation of the bladder without exertion of any forces on the outer shell.

3. An oxygen supply system as claimed in claim 2 wherein the outer shell of the helmet is adapted to provide a mounting for optical components which are to be aligned with the head of the wearer.

4. An oxygen supply system as claimed in claim 2 or 3 wherein the at least one strap is integral with an inner portion of the helmet, the inner portion comprising releasable anchoring points for the outer shell such that the bladder and inner portion of the helmet can be securely affixed to the head of the wearer prior to the outer shell

being affixed to the anchoring points.

5. An oxygen supply system as claimed in claim 2 or 3, wherein the bladder is

retained in the recess.

6. An oxygen supply system substantially as hereinbefore described with reference

to the accompanying drawings.