GB2417905A

GB2417905A - Breathing mask mounting harness

Info

Publication number: GB2417905A
Application number: GB0420192A
Authority: GB
Inventors: Joseph Anthony Griffiths
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-09-10
Filing date: 2004-09-10
Publication date: 2006-03-15
Also published as: GB0420192D0

Abstract

A harness for attaching a breathing mask 41 to a pilot's helmet 40 so that the mask 41 makes a seal around the pilot's nose and mouth. The harness comprises a pair of wires 60a, 60b that extend, when the mask is worn, between the mask 41 and the helmet 40 on either side of the pilot's face. The wires 60a, 60b of each pair are mounted to the mask and helmet so that they cross over each other therebetween.

Description

24 1 7905 Breathing Mask Mounting Harness

Description

s The present invention relates to a breathing mask for use by pilots and, in particular, to a harocss for mounting a breathing mask to a pilot's flying helmet.

Pilots of modern fighter aircraft are provided with breathing facemasks to supply breathable gas such as air or oxygen-enriched air to them during flight. These masks are generally mounted by a harness to a flying helmet which the pilot wears during flight.

It is esscotial that the mask makes an airtight seal with the pilot's face at all times. If the pilot is flying at high altitude, the atmospheric pressure within the cockpit will be lower than at ground level and so he will require the breathable gas to be supplied to him via the mask at higher pressure than the air of his surroundings. In these circumstances, the pilot simply ensures that the tension in the harness is sufficient to maintain the airtight seal of the mask with his face.

If the pilot is flying a modern fighter aircraft capable of executing manoeuvres which subject the pilot to excessive G-forces, he will require the breathable gas to be supplied to him at an elevated pressure by a breathing gas regulator. The breathing gas regulator is responsive to Gforces which the pilot is subjected to, such that when the G-force increases, the pressure at which the breathing gas is supplied increases. Conversely, when the G-force reduces, the regulator reduces the breathing gas pressure. If the pilot does not receive his supply of breathing gas under the correct pressure, for example, if the mask seal fails, then there is a significant risk that he will black out, i.e. experience 'GLOC' (G-force Loss Of Consciousness'). However, the G-forces exerted on the pilot also affect the mask, and tend to force the mask downwards on the pilot's face. If the mask is allowed to move too far down on the pilot's face, the air-tight seal therewith will fail and deprive the pilot of the essential pressurised breathing gas supply. - 2

Modern fighter aircraft arc now capable of performing manoeuvres at up to 9G and in such circumstances, the forces exerted on the mask are very high. Various mask arrangements are known which are designed to counteract this tendency for the mask to slip down the pilot's face under high-G situations. For example, the s Appllcant's own earlier UK patent application no. 0221687.7 discloses a mask having an expandable section in the lower portion of the mask which, when pressurlsed gas is supplied to the interior of the mask, expands further than a corresponding expandable section in the top of the mask. This tilts the mask upwards about the attachment point of the harness holding the mask to the helmet, and helps prevent the mask from slipping down the pilots face. However, this system still uses a conventional single-strap harness to attach the mask to the helmet, which, in itself, is not designed to resist mask-slp under high G-forces.

Therefore it is desirable to provide an improved harness arrangement to prevent this mask slip, but which also allows the mask to tilt, so that, if desired, the harness can be used in conjunction with the mask described in the Applicant's earlier patent application.

Therefore, it is an object of the present invention to provide a mask harness arrangement which substantially alleviates or overcomes the problems mentioned above.

According to the present invention, therefore, there is provided a harness for attaching a breathing mask to a pilot's helmet so that the mask makes a seal around the pilot's nose and mouth, the harness comprising a pair of wires that extend, when the mask is worn, between the mask and the helmet on either side of the pilot's face, the wires of each pair being mounted to the mask and helmet so that they cross over each other therebetwcen.

In a preferred embodiment, the wires are attached at one end thereof to a bracket and the bracket is mountable to a pilot's helmet, and is preferably substantially a sideways 'T'-shape. The bracket may be one unitary body, or alternatively may be formed of two separate components secured to one another. - 3

The two separate components are preferably adjustably secured to one another, and in a preferred embodiment, the two components incorporate a lip and groove arrangement formed on contacting surfaces thereof, which engage when said contacting surfaces are brought together and are operable to prevent rotational s movement of a first componcut relative to a second component.

In a preferred embodiment, a first component comprises a first solid elongate plate and a second component comprises a second elongate plate with a slot along the length thereof, wherein the second plate is secured to the first plate by a screw or bolt which extends through the slot in the second plate and is threadingly received in a hole in the first plate. Conveniently, two screws or bolts secure the second plate to the first plate.

The first plate is preferably received in a housing, the housing being attachable to the side of a helmet to secure the bracket thereto, the first plate preferably being slidably received in the housing so at to be adjustably positioned relative thereto.

In a preferred embodiment, the first plate includes a plurality of ridges on one side thereof, and the housing includes a tooth which is engageable with said ridges to secure the first plate in a chosen fixed position relative to the housing.

The said one end of each wire is preferably attached proximate each end of the second elongate plate. Conveniently, at least one wire includes an adjustment mechanism operable to allow the length of the wire to be altered, however, both wires may include an adjustment mechanism. In a preferred embodiment, the wires are made from metal, or alternatively, the wires may be made from a plastic material. Preferably, the wires are inextensible The present invention also provides a pilot's breathing mask incorporating a harness as described above, and also provides a pilot's flying helmet incorporating said mask. - 4

A preferred embodiment of the present invention will now be described, by way of example only, with reference to Figures 5 and 6 of the following Figures, in which: Figure 1 is a side view of a pilot wearing a helmet and mask with a prior art harness; s Figure 2 is the masks of Figure 1 when subjected to high G-force; Figure 3 is a side view of a pilot wearing a helmet and mask with another type of

prior art harness;

Figure 4 is the mask of Figure 3 when subjected to high G-force; Figure 5 is a side view of a pilot wearing a helmet with a mask attached by a harness according to the present invention; and Figure 6 is a close up of the mask arrangement of Figure 5.

Referring now to Figure 1, a prior art mask and helmet arrangement is shown comprising a helmet 10 and a mask 11. The mask 11 generally comprises a rigid shell 12 housing a flexible oro-nasal portion 13. The oro-nasal portion 13 has a peripheral edge 14 which, in use, makes a seal around the pilot's nose and mouth.

The mask 11 is attached to the helmet 10 by two inextens1ble wires 15, one on each side of the helmet 10 (one of the wires 15 is not visible in the drawing). Each wire extends between a hrst attachment point 16 located on an edge of the mask 11, and a second attachment point 17 located on the helmet 10.

Figure 2 shows what happens when the prior art mask arrangement shown in Figure 1 is subjected to high G-forces. The G-forces act on the mask 11 in the direction shown by arrow 'G' and cause it to pivot downwards about the second attachment point 17 and slip down the pilot's face from its original position shown in dashed lines, to the position shown in solid lines. As the mask 11 slides downwards, the peripheral edge 14 of the oronasal portion 13 comes away from the pilot's face and the seal therebetween is broken. This allows the pressurised breathable gas to leak out from within the mask 11 resulting in the pilot being deprived of oxygen, leading to G-LOC, with potentially fatal consequences.

Another known mask attachment arrangement is illustrated in Figure 3. As with the arrangement shown in Figures 1 and 2, there is a helmet 20 and a mask 21, the mask - 5 21 comprising a rigid shell 22 and a flexible oro-nasal portion 23 having a peripheral edge seal 24. However, the mask 21 is attached to the helmet 20 on each side thereof by two separate substantially parallel wires 25a, 25b. Each wire 25a, 25b is respectively connected between a first connection point 26a, 26b on the mask 21 s and a second connection point 27a, 27b on a bracket 28 which is attached to the helmet 20. Each bracket 28 is 'V'-shaped and on one arm 29 of the 'V' are the second connection points 27a, 27b and, the other arm 30 of the 'v' is slidingly received in a housing 31 mounted on the helmet 20, and can be fixedly secured therein. This arrangement is designed so that when the pilot dons the helmet 20, he can loosely position the mask 21 over his nose and mouth, and then slide the bracket 28 on each side of the helmet 20 rearwardly away from his face so that the other arm 30 slides though the housmg 31 and can be secured therein to tension the wires 25a, 25b and hold the mask 21 firmly against his face.

Figure 4 shows what happens when the mask 21 of Figure 3 is subjected to excessive G-forces. As with the mask 11 of Figures 1 and 2, the G-forces acts in a direction indicated by arrow 'G' and push the mask 21 downwards on the pilot's face from the correct position shown in dashed lines, to the shifted position shown in solid lmes. Even though this second prior art embodiment includes two wires 25a, 25b each side of the mask 21 to attach it to the helmet 20, they are both still able to pivot about their respective second connection points 27a, 27b, allowing the mask to move downwards, thereby causing the edge 24 of the oro-nasal portion 23 of the mask 21 to come away from the pilot's face with the same consequences as mentioned above.

In order to overcome the above prior art problems, a mask attachment harness according to the present invention is shown in Figures 5 and 6. This comprises a helmet 40 and a mask 41. The mask 41 comprises a rigid shell 42 housing a flexible oro-nasal portion 43. The oro-nasal portion 43 has a peripheral edge 44 which, in use, makes a seal around the pilot's nose and mouth.

The mask 41 is attached to the pilot's helmet 40 on each side thereof by a cross-wire spring arrangement comprising a 'T' bracket 50 and first and second wires 60a, 60b. - 6

The 'T' bracket 50 consists of two separate elements, a slide plate 51 and a ratchet plate 52, which, m use, are arranged perpendicular to one another, as shown in the drawings. The first wire 60a extends from a first helmet connection point 61a at a top portion of the slide plate 51, diagonally forwards and downwards to a first mask s connection point 62a located on the shell 42 of the mask 41. The second wire 60b extends from a second helmet connection point 61b at a bottom portion of the slide plate 51, diagonally forwards and upwards to a second mask connection point 62b located on the shell 42 of the mask 41, above the first mask connection point 62a.

The ratchet plate 52 includes a screw 54, having a head and a shank, threadingly received in one end, and has a series of ridges 55 formed on one side thereof. The slide plate 51 has an elongate slot 53 formed therein, and the shank of the screw 54 passes through the slot 53 so that when the screw 54 is tightened, the head of the screw 54 engages with a surface of the slide plate 51 to secure the slide plate 51 to the ratchet plate 52. The ratchet plate 52 is slidably received in a housing 56 connected to the helmet 40, so that the ratchet plate 52 and associated slide plate 51 can be moved forwards and backwards withm said housing 56, towards and away from the pilots face, and retained in a chosen position by a ratchet tooth (not shown) in the housing engaging with a ridge 55 of the ratchet plate 52.

In addition to the ratchet plate 52 being moveable in the housing 56, the slide plate 51 is also moveable relative to the ratchet plate 51. This is achieved by loosening the screw 54 that clamps the slide plate 51 to the ratchet plate 52 and sliding the slide plate 51 up or down as required, with the shank portion of the screw 54 remaining located within the slot 53. When the slide plate 51 is in the desired position, the screw 54 is simply tightened again and the slide plate 51 is clamped in place on the ratchet plate 52.

In use, when the helmet 40 and mask 41 are worn by a pilot, the 'T' bracket 50 is adjusted so that the wires 60a, 60b are held taut and the mask 41 is held sufficiently firmly against the pilot's face so that the peripheral edge 44 of the oro-nasal portion 43 makes an airtight seal therewith. - 7

When the pilot makes a high-G turn, the G-forccs exerted on the mask act in the direction shown by arrow 'G'. However, unlike the prior art masks 11, 21 shown in Figures 1 - 4, the mask 41 of the present invention does not slip down the pilot's face in the direction of the arrow 'G'. This is because the first wire 60a is positioned s at such an angle to the horizontal as shown in the Figures, that the force urging the mask 41 to slip down the pilots face is transmitted along the length of the first wire 60a to the helmet 40 and an equal and opposite restraining force is transmitted back along the length of the first wire 60a which acts on the mask 41 at the first mask connection point 62a. The angle of the first wire 60a means that a vertical component of the tensile resistance of the first wire 60a is sufficient to keep the mask 41 from moving in a vertical direction down the pilot's face. As the mask 41 is therefore vertically restrained at the first mask connection point 62a, the only degree of movement available to it is in a rotational forwards direction about a pivot point of the first mask connection point 62a. However, this movement is prevented by the second wire 60b. The diagonal angle of the second wire 60b is such that a horizontal component of the tensile resistance of the second wire 60b acting on the mask 41 at the second mask connection point 62b is sufficient to prevent the mask 41 tilting forward.

Despite the restriction in vertical slip movement of the mask 41 described above, it will be appreciated that the connection mechanism of the invention still allows the mask to pivot inwardly towards the pilot's face about the first mask connection point 62a. This feature is important if the oro-nasal portion 43 of the mask 41 incorporates an expandable section as mentioned above and described in our earlier UK patent application no. 0221687.7. In this case, when pressurlsed breathable gas is supplied to the interior of the mask 41, the bottom region of the oro- nasal portion 43 will expand more than the upper region. This pushes the bottom of the mask 41 around the first mask connection point 62a away from the pilot's face and, due to the inextensible nature of the first connection wire 60a, the mask will pivot upwardly about the first helmet connection point 61a. However, due to the inextensible nature of the second mask connection wire 60b, the top of the mask is pulled towards the pilot's face. This movement of the top of the mask 41 tilting towards the pilot's face and the bottom tilting away from the pilot's face, together l - 8 with the increase in tension in the wires 60a, 60b caused by the expanded section of the oro-nasal mask 43, results in the mask 41 bemg pulled tighter onto the pilot's face and reinforces the airtight seal therewith, and positions the mask 41 so as to more securely resist slipping down the pilot's face.

Various unillustrated embodiments of the mask attachment means are intended to fall within the scope of the invention. For example, the ratchet plate 52 could include two screws 54 threadingly received therein instead of just one. This would hold the slide plate 51 securely in its perpendicular orientation relative to the ratchet plate 52, as the slide plate 51 would not be able to rotate about the axis of the shank of the screw 54 when the screw 54 is loosened, as it can in the single screw embodiment shown in Figures 5 and 6. In such a two-screw embodiment, the tightening of the screws therefore only serves to retain the slide plate 51 in a chosen lateral position perpendicular to the ratchet plate 52 and does not serve to prevent rotation of the slide plate 51 relative to the ratchet plate 52.

As an alternative to having two screws 54 to prevent rotation of the slide plate 51 relative to the ratchet plate 52, the contacting faces of the two plates could include a cooperating lip and groove arrangement wherein a lip on one plate would sit in a groove on the other and would allow the slide plate 51 to move in a single plane perpendicular to the length of the ratchet plate, but prevent rotational movement relative thereto.

In addition to the above embodiments wherein the slide plate 51 and ratchet plate 52 which make up the 'T'- bracket 50 are adjustable relative to one another, it is intended that the present invention also includes non- adjustable embodiments. In such an embodiment, the 'T'-bracket 50 could be formed as one unitary body. In such an embodiment, the ratchet plate could be adjustable only with respect to the housing 56 connected to the helmet 40. In another embodiment, the ratchet plate 52 could be rigidly fixed to the helmet and the slide plate could be adjustable relative thereto as described above, or in an even simpler embodiment, the whole 'T' - bracket 50 could be one unitary body non-adjustably secured to the helmet. l - 9 -

It is also cnv1saged that an embodiment of the invention may include wire adjustment means provided along the length of each wire 60a, 60b, so that the length of each wire 60a, 60b respectively can be individually adjusted to improve the fit on the ptlot's face. -

Claims

Claims 1. A harness for attaching a breathing mask to a pilot's helmet so

that the mask makes a seal around the pilot's nose and mouth, the harness comprising a pair of s wires that extend, when the mask is worn, between the mask and the helmet on either side of the pilot's face, the wires of each pair being mounted to the mask and helmet so that they cross over each other therebetween.
2. A harness according to claim I wherein the wires are attached at one end thereof to a bracket, the bracket being mountable to a pilot's helmet.
3. A harness according to claim 2 wherein the bracket is substantially a sideways 'T'-shape.
4. A harness according to claim 3 wherein the bracket is one unitary body.
5. A harness according to claim 3 wherein the bracket is formed of two separate components secured to one another.
6. A harness according to claim 5 wherein the two separate components are adjustably secured to one another.
7. A harness according to 5 or 6 wherein the two components incorporate a lip and groove arrangement formed on contacting surfaces thereof, which engage when said contacting surfaces are brought together and are operable to prevent rotational movement of a first component relative to a second component.
8. A harness according to claim 6 or claim 7 wherein a first component comprises a first solid elongate plate and a second component comprises a second elongate plate with a slot along the length thereof, wherein the second plate is secured to the first plate by a screw or bolt which extends through the slot in the second plate and is threadingly received in a hole in the first plate.
9. A harness according to claim wherein two screws or bolts secure the second plate to the first plate.
10. A harness according to claim 8 or claim 9 wherem the first plate is received in a housing, the housing being attachable to the side of a helmet to secure the bracket thereto.
11. A harness according to claim 10 wherein the first plate is slidably received in the housing so at to be adjustably positioned relative thereto.
12. A harness according to claim 11 wherein the first plate includes a plurality of ridges on one side thereof, and the housing includes a tooth which is engageable with said ridges to secure the first plate in a chosen fixed position relative to the housing.
13. A harness according to any of claims to 12 wherein the said one end of each wire is attached proximate each end of the second elongate plate.
14. A harness according to any preceding claim wherein at least one wire includes an adjustment mechanism operable to allow the length of the wire to be altered.
15. A harness according to claim 14 wherein both wires include an adjustment mechanism.
16. A harness according to any preceding claim wherein the wires are made from metal.
17. A harness according to any of claims 1 -15 wherein the wires are made from a plastic material.
18. A harness according to any preceding claim wherein the wires are inextensible. - 12
19. A harness substantially as herenbefore described with reference to the accompanying drawings.

s
20. A pilot's breathing mask incorporating a harness according to any preceding claim.
21. A pilot's helmet incorporating a breathing mask according to claim 20.