GB2210772A

GB2210772A - Aircrew respirator

Info

Publication number: GB2210772A
Application number: GB8723813A
Authority: GB
Inventors: John Stuart Tweedie; Gordon Edward Thorne
Original assignee: Negretti Aviation Ltd
Current assignee: Negretti Aviation Ltd
Priority date: 1987-10-09
Filing date: 1987-10-09
Publication date: 1989-06-21
Anticipated expiration: 2007-10-09
Also published as: GB2210772B; GB8723813D0

Abstract

The respirator has a hood 2 and a faceplate 1 providing an optical area 4 and a housing 5 for an oxygen mask. The hood has an opening 12 dimensioned so that the faceplate 1 fits within it leaving a small gap. A strip 6 bridges across the gap to seal the faceplate to the hood, and a second shorter, tab strip 16 overlies a part of the first strip with one edge extending substantially in alignment with the gap. One end of the second strip has pulling means 17 for initiating a rip along the gap to enable the faceplate to be ripped off by the user in an emergency. Preferably the first longitudinal strip is a ring of "T"-cross section (Figs. 2, 2a), the cross part (7a, 7b, Fig. 4) of which is adhered to the periphery of the faceplate and hood around said opening on respective sides of its leg (8) which is doubled back over the edge of the faceplate and adhered to the inner periphery thereof. <IMAGE>

Description

AIRCREW RESPIRATORS This invention relates to aircrew respirators.

An aircrew respirator of a type generally known as an AR5, comprises a faceplate incorporating an optical area and a housing for breathing apparatus, and a hood part which fits over the head of the wearer beneath his flying helmet and has an opening which is sealed around the face plate. Normally, an apron and bellows is sealed around the lower edge of the hood part to sit on the wearer's shoulders. The AR5 must be proof against nuclear, biological and chemical (NBC) agents and, hence, it is essential that an effective and reliable seal be provided between the faceplate and hood opening. Furthermore, the seal must be capable of being ripped open in the event of an emergency, eg for a crash landing. One example AR5 is described in U.K.Patent Specification No 2148697, in which the faceplate and hood are sealed together, and a longitudinally grooved strip extends around the hood material close to where it is sealed to the periphery of the faceplate and overlies a butt-joint in the hood material. In manufacturing the AR, the strip is adhered to the hood material so that its longitudinal groove is on the undersurface and the butt joint is subsequently formed by a sharp knife from inside the hood using the groove as a guide line.

The object of the present invention is to provide an alternative arrangement which does not require such a longitudinally groove strip.

According to the present invention, an aircrew respirator comprising a faceplate and a hood part is characterised in that the hood is formed with an opening which is dimensioned so that the faceplate fits within it with a small gap, in that a longitudinal strip bridges across the gap to seal the faceplate to the hood, and in that a second, shorter, longitudinal tab strip overlies a part of the first strip with one edge substantially in alignment with the gap, one end of the second strip being provided with pulling means for initiating a rip along the gap.

Preferably the first longitudinal strip is of "T"-cross section, the cross-part of which is adhered to the periphery of the faceplate and hood opening on respective sides of the leg, the leg being doubled back over the edge of the faceplate and adhered to the inner periphery thereof.

In order that the invention may be readily understood and further features made apparent, one embodiment of AR5 will now be described with reference to the accompanying drawings, in which: Fig 1 is a front view of the AR5, Fig 2 is a front view of the first longitudinal strip, Fig 2a is a detail on the line A-A of Fig 2, Fig 3 is a side view of Fig 2, and Fig 4 is a cross-sectional view showing the attachment of the faceplate and hood via said strip.

Referring to Figure 1 the AR5, as known per se, comprises a faceplate 1, preferably of a rigid polycarbonate, and a hood 2 and apron 3, preferably of a bromo butyl rubber. The faceplate 1 is formed with an optical area 4 and, below this area, a housing 5 for an oxygen mask. In accordance with the invention, a longitudinal strip 6 bridges across the periphery of the faceplate and the hood to seal the two parts together.

Referring to Figs 2 and 3, the longitudinal strip 6 is formed as a ring 7 moulded from a suitable rubber like material, eg NEOPRENE, with a leg 8 extending perpendicular therefrom; in cross-section it is of "T"-shape as shown in Fig 2a. The ring 7 and leg part 8 are formed with opposed angular shaped parts 9 and 10, the purpose of which is to fit to a necked area 11 (see Figure 1) of the faceplate and hood between the optical area 4 and housing 5.

Referring now to Figure 4, the ring 7 forming the crosspart of the "T"-shaped moulding is first bonded by an approved cold cure, vulcanising, adhesive on one side, 7a of its leg to the front face of the faceplate 1, so that the leg 8 closely abuts the periphery of said faceplate. The leg 8 is then doubled back to lap over the edge of the faceplate and is bonded to the inside face of the faceplate. The part 7b of the ring 7 is then bonded progressively around its co-operating opening 12 in the hood 2. In this embodiment, the thickness of the moulded ring and leg is between 0.60-0.80mm and it is intended that a gap 13 of 1-2mm be left between the leg 8 and the adjacent edge of the opening 12.This gap not only provides a line of weakness around the faceplate for ripping apart, but also reduces the possibility of the bonding agent acting between said leg and adjacent edge of the opening to provide "strength bridges" across the said gap.

It will be noted that the ring part 7b is longer than the part 7a; this is because a bonding overlap of approx 6mm is preferred and the longer part 7b is to allow for the width of the leg 8 and said gap. As shown in Figure 4, the ring 7 is coated over with a bromo butyl wash 14 to act as additional protection, particularly against chemical penetration. Also, a comfort strip 15 is provided around the faceplate over the leg 8.

Referring again to Figure 1, a second relatively short tab strip 16 is bonded over the ring 7 so that one edge 16a is in alignment with the gap 13. One end of the strip is left unbonded and has a toggle 17 fixed thereto. Thus, the strip and toggle provide a rip tab to initiate a tear along the edge of the faceplate in an emergency. After initiating the tear, the wearer then grasps the partially ripped out part of the edge of the faceplate to pull it and continue the tear around the periphery of the faceplate, thenty separating the hood from the faceplate.

Claims

1. An aircrew respirator comprising a faceplate providing an optical area and a housing for an oxygen mask, and a hood, characterised in that the hood (2) is formed with an opening (12) which is dimensioned so that the faceplate (1) fits within it with a small gap, in that a longitudinal strip (6) bridges across the gap to seal the faceplate to the hood, and in that a second, shorter, longitudinal tab strip (16) overlies a part of the first strip with one edge extending substantially in alignment with the gap, one end of the second strip being provided with pulling means (17) for initiating a rip along the gap

2. An aircrew respirator according to Claim 1.

further characterised in that the first longitudinal strip is of "T"-cross section, the cross-part (7a, 7b) of which is adhered to the periphery of the faceplate and hood around said opening on respective sides of the leg (8), the leg being doubled back over the edge of the faceplate and adhered to the inner periphery thereof.

3. An aircrew respirator according to Claim 1 or 2, further characterised in that the longitudal strip (6) is formed as a ring (7) moulded from a suitable rubber like material, eg NEOPRENE, and in that the said ring is formed with opposed inwardly extending angular shaped parts (9) for fitting to a necked area (11) of said faceplate between said optical area (4) and housing (5).

4. An aircrew respirator according to Claim 3, further characterised in that the ring (7) forming the cross-part of the "T"-shape strip is first bonded by an approved cold cure, vulcanising, adhesive on one side, (7a) of its leg to the front face of the faceplate (1), so that the leg (8) closely abuts the periphery of said faceplate, in that the leg is then doubled back to lap over the edge of the faceplate and is bonded to the inside face of the faceplate and in that the part (7b) of the ring is then bonded progressively to the hood (2) around its opening.

5. An aircrew respirator according to Claim 3 or 4, further characterised in that the thickness of the moulded ring and leg is between 0.60-0. 80mm and it is intended that a gap (13) of 1-2mm be left between the leg 8 and the adjacent edge of said opening, said gap providing a line of weakness around the faceplate for ripping apart, and reducing the possiblity of the bonding agent acting between said leg and adjacent edge of the opening to provide "strength bridges11 across the said gap.

6. An aircrew respirator according to any one of Claims 3 to 5, further characterised in that the ring (7) is coated with a bromo butyl wash (14) to act as additional protection, particularly against chemical penetration, and in that a comfort strip (15) is provided around the faceplate over the leg (8).

7. An aircrew respirator constructed. arranged and adapted for use substantially as hereinbefore described with reference to the accompanying drawings.