GB2540153A

GB2540153A - Respirator with adjustable visor

Info

Publication number: GB2540153A
Application number: GB1511848.2A
Authority: GB
Inventors: Anthony Griffiths Joseph
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-07-07
Filing date: 2015-07-07
Publication date: 2017-01-11
Anticipated expiration: 2035-07-07
Also published as: GB2540153B; GB201511848D0

Abstract

A respirator 1, particularly suitable for use by military infantry combat usage, comprises an oro-nasal mask 2 configured to surround a wearers nose and mouth, a visor 3 pivotally mounted to the oro-nasal mask, a peripheral face seal 4 to surround a wearers face, and a gas-impermeable layer/membrane 5 which extends between the peripheral face seal and the visor in use. The peripheral face seal comprises a resilient reinforcing element 32 (e.g. a steel band or bead) which may be embedded in a portion of the seal. The mask may be connected to the seal by at least one strap (22, Fig 3) on either side of the mask and/or one strap may be provided on the mask, extending through the gas impermeable layer/membrane for connecting the mask to a helmet having suitable connection elements.

Description

Respirator with Adjustable Visor Field

This invention relates to a respirator and, in particular, to a respirator which incorporates an adjustable visor and which is suitable for use by military infantry combat personnel.

Background

Infantry personnel are required to operate in a variety of combat environments and are provided with varied specialist equipment to enable them to perform their duties. One such environmental factor infantry must be able to cope with is harmful atmospheric conditions, such as in the use of biological or chemical weapons. In such circumstances, infantry would be required to wear a respirator as part of their combat equipment. A respirator is a face mask that seals around the wearer’s face and includes an oro-nasal mask that locates around the wearer’s nose and mouth, and a visor or window portions in line with the wearer’s eyes.

In order to operate effectively, infantry personal must be able to use their weapons with minimal encumbrance from their equipment. Modern optical sighting systems for assault rifles include electronic scopes which require precise alignment with the wearer’s aiming eye. If an electronic scope is of out of alignment, the wearer cannot see through the scope at all and so the scope is ineffective. A problem with current respirators available for military personnel is that they are bulky and the window portions are spaced relatively far from the wearer’s eyes. This is problematic in that the bulky respirator spaced from the wearer’s face prevents a weapon being used from being placed near the wearer’s face. For example, a wearer is not able to place the butt of a rifle against or close to their cheek as they would otherwise be able to do if they were not wearing a respirator. This means that it is very awkward, if not impossible, for a wearer to align their aiming eye with the electronic scope, making using the rifle very difficult. In addition, the window portions being relatively far spaced from the wearer’s eyes adds to the difficulty of getting the electronic scope close to and aligned with the wearer’s aiming eye. A further problem with many current respirators is that the window portions are fixed relative to the mask seal, which results in the position of the window portions relative to a wearer’s eyes varying from person to person, dependent upon the wearer’s head shape.

It is therefore an object of the present invention to provide a respirator that substantially alleviates of overcomes one or more of the problems mentioned above.

Summary

According to the present invention, there is provided a respirator comprising an oro-nasal mask configured to surround a wearer’s nose and mouth, a visor pivotably mounted to the oro-nasal mask, a peripheral face seal to surround a wearer’s face, the peripheral face seal comprising a resilient reinforcing element, and a gas-impermeable layer extending between the peripheral face seal and the visor.

The peripheral face seal may comprise an annular member and the resilient reinforcing element may be embedded within the annular member.

The peripheral face seal may comprise a moulded annular member and the resilient reinforcing element may be embedded within the moulded annular member.

The peripheral face seal may comprise an annular member comprising a laminar structure and the resilient reinforcing element may be disposed between two or more layers of the laminar structure.

The peripheral face seal may comprise an annular member and the resilient reinforcing element may be bonded to the annular member.

The peripheral face seal may comprise an annular member and the resilient reinforcing element may extend entirely around the annular member.

The peripheral face seal may comprise an annular member and a plurality of spaced resilient reinforcing elements may be provided within the annular member.

The or each resilient reinforcing element may comprise a steel band or bead, and/or may comprise a glass fibre reinforced polymer element.

The oro-nasal mask may be connected to the peripheral face seal by at least one strap on each side of the oro-nasal mask. Each strap may be made of an inextensible material.

The straps may include adjustors to enable the length of the strap between the peripheral face seal and the oro-nasal mask to be adjusted.

The respirator may comprise a connection mechanism to secure the straps to the peripheral face seal, and the connection mechanism may be configured to enable the straps to be secured in a plurality of different positions on the peripheral face seal.

The connection mechanism may comprise a first fastener on each strap and a plurality of second fasteners on each side of the peripheral face seal, and the first and second fasteners maybe engageable to connect the straps to the peripheral face seal.

The oro-nasal mask may include at least one strap on each side of the oro-nasal mask extending through the gas-impermeable layer and configured to connect the oro-nasal mask to a helmet having cooperating connection elements. A seal may be provided at the interface where the straps pass through the gas-impermeable layer.

The peripheral face seal may comprises a first section for contacting the wearer’s face, and a second section extending from the first section, and the impermeable layer may be bonded to the second section.

The first section may comprise an annular member having first and second peripheral edges, and the second section may comprise a flange extending from between the first and second edges.

The first and second peripheral edges may comprise flat lip sections configured to lie flat against a wearer’s face.

The first section of the peripheral face seal maybe concave in cross-section in an undeformed state.

The gas-impermeable layer may extend between the peripheral face seal and the visor around the entire perimeter of the peripheral face seal and visor such that, in use, the oro-nasal mask is contained within a closed space defined by the wearer’s face, the visor, the peripheral face seal and the gas-impermeable layer.

The respirator may comprise an adjustable mounting mechanism connecting the visor to the oro-nasal mask and configured such that the angle of the visor relative to the oro-nasal mask can be adjusted.

The adjustable mounting mechanism may include a locking mechanism to enable the visor to be locked in a selected position relative to the oro-nasal mask.

The respirator may comprise an inlet port for the inlet of breathable air into the respirator, and the inlet port may include a coupling mechanism for connecting a filter cartridge and/or breathable air supply line to the respirator.

The respirator may comprise a plurality of inlet ports such that a user can select which location to connect a filter cartridge and/or breathable air supply line to the respirator. The inlet ports may be provided in at least two locations of a left side of the respirator, a right side of the respirator and a central position on a lower region of the respirator.

The peripheral face seal may comprises a harness including a plurality of straps to secure the respirator in place on a wearer’s head.

The gas-impermeable layer extending between the peripheral face seal and the visor may comprise a fabric layer.

Brief Description of the Drawings

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure l is a front view of an embodiment of a respirator of the present invention;

Figure 2 is a side view of the respirator shown in Figure 1;

Figure 3 is an exploded perspective view of the respirator of Figures 1 and 2;

Figure 4 is a perspective cut away view of the respirator shown in Figures 1 to 3, in position on a wearer’s face;

Figure 5 is a side cut away view of the respirator shown in Figures 1 to 3, in position on a wearer’s face;

Figure 6 is a cross-sectional view along the line X-X in Figure 3 showing the peripheral face seal;

Figures 7A and 7B are cross-sectional views showing conventional respirator face seal configurations;

Figure 8A is a cross-sectional view along the line X-X in Figure 3 showing a peripheral face seal of an alternative embodiment of the invention;

Figure 8B is a cross-sectional view of the peripheral face seal of Figure 8A against a wearer’s head, in a first orientation;

Figure 8C is a cross-sectional view of the peripheral face seal of Figure 8A against a wearer’s head, in a second orientation;

Figure 9 is a perspective view of a peripheral face seal and inner mask of a further alternative embodiment of the invention.

Detailed Description

Referring now to Figures 1-5, there is shown an embodiment of a respirator 1 of the invention comprising an inner mask 2, a visor 3 mounted to the inner mask 2, and a reinforced peripheral face seal portion 4 (referred to hereafter as “face seal”). A membrane 5 made of a gas-impermeable material extends between a perimeter edge 6 of the face seal 4 and an outer edge 7 of the visor 3. (The membrane 5 is omitted from Figure 1 for ease of illustration of other components). The inner mask 2 comprises an oro-nasal mask and has a peripheral rim adapted to make a seal around a wearer’s nose and mouth.

The visor 3 includes a window 8 and a mounting plate 9, the window 8 being connected to the mounting plate 9 by a bridge portion 10. The inner mask 2 includes a pivot boss 11 having a horizontal aperture 12 extending therethrough. The visor 3 is pivotally mounted to the inner mask 2 by the mounting plate 9 being pivotally connected to the pivot boss 11. In the exemplary embodiment shown, this is by a pin 13 extending through holes 14 in side flanges 15 of the mounting plate 9 and through the aperture 12 in the pivot boss 11. However, alternative configurations of mechanical pivotal connections are intended within the scope of the invention.

The face seal 4 comprises an annular member and is a continuous band of material which is configured to sit on and seal against a wearer’s face. The face seal 4 is configured to seat around the forehead, sides of the head along the temples and cheeks and around the chin. The chin portion is preferably cup-shaped to receive and effectively seal against a wearer’s chin. This also helps retain the face seal 4 in position on a wearer’s face.

The respirator 1 includes a harness 16 to enable the respirator 1 to be secured on the head of a wearer, for example, an infantry person, and to hold the face seal 4 in sealing engagement with the wearer’s face. In the exemplary embodiment shown, the harness 16 comprises an upper strap 17, middle straps 18 and lower straps 19. These straps 17, 18,19 extend from the face seal 4 and meet at a rear section 20 located at the rear of the wearer’s head when in use. The harness 16 is made of a flexible material such as rubber, and may include adjustors 21 to enable the length of the upper, middle and lower straps 17,18,19 to be adjusted to suit different head shapes/sizes.

The inner mask 2 is secured to the face seal 4 by straps 22 on each side of the inner mask 2/face seal 4. The straps 22 include adjustable connectors 23 to allow the length of each strap 22 between the inner mask 2 and the face seal 4 to be adjusted. This allows the inner mask 2 to be moved forwards and backwards relative to the face seal 4 to accommodate different face shapes of different wearers. However, the material of the strap is inextensible so does not stretch in use. This ensures that once the adjustable connectors are set to the correct length for a particular wearer, when the respirator 1 is fitted on the wearer’s face/head, the distance between the inner mask 2 and the face seal remains constant. Since the visor 3 is mounted to the inner mask 2, this helps ensure that once the visor 3 is adjusted to the correct position relative to a wearer’s face and eyes, this visor distance does not change during use.

The straps 22 are connected to the inner mask 2 at a point about which the inner mask can pivot to accommodate different wearer face shapes, for example, different size and degrees of protrusion of noses and chins. The straps 22 preferably extend from the inner mask 2 to the face seal 4 substantially horizontally to allow the optimum balance of inner mask on a wearer’s face to be achieved. Figure 2 shows the relative position of the straps 22 and the wearer’s line of sight. The connecting pivot point 37 of the straps 22 on the inner mask 2 is disposed below the eye level 38 of the wearer (that is, a line extending horizontally from the wearer’s eyes) by distance ‘d’. Distance d may be between 2.5 - 5cm, and is preferably around 3.5 - 4.0 cm. In alternative embodiments of the invention, the straps 22 may be replaced by inextensible wires or cables securing the inner mask 2 to the face seal 4.

The angle of the visor 3 relative to the inner mask 2 can be adjusted by means of a tilting mechanism 24 provided on the front of the mounting plate 9. In use, since the face seal 4 is fixed relative to the wearer’s face, and the inner mask 2 is held in a fixed position on the wearer’s face, the angle of the visor 3 is therefore also adjustable relative to the face seal 4.

The tilting mechanism 24 comprises a knob 25 connected to a threaded shaft 26. An end of the threaded shaft 26 remote from the knob 25 is secured to the pivot boss so as to be rotatable relative to the pivot boss 11 but not moveable in an axial direction of the threaded shaft 26 relative to the pivot boss 11. A threaded plate 27 is disposed on the front of the mounting plate 9 and is fixed relative thereto. The threaded shaft 26 is threadingly engaged with a threaded aperture 28 in the threaded plate 27. In use of this tilting mechanism 24, rotation of the knob 25 causes the threaded plate 27 to move towards or away from the pivot boss 11 of the inner mask 2. This causes the mounting plate 9 to move towards or away from the pivot boss and thereby the visor 3 to pivot relative to the inner mask 2 about the pin 13, as shown by arrow T in Figures 2 and 5. The visor window 8 can thereby be moved forwards or backwards relative to the inner mask 2.

The membrane 5 which seals between the outer edge 7 of the visor 3 and the face seal 4 is gas impermeable so that, once the respirator 1 is in place on a wearer’s face with the face seal 4 sealing around the wearer’s face, the wearer’s face is completely sealed from external ambient environmental atmosphere by the membrane 5 and the solid visor 3. The inner mask 2 is contained within the visor 3 and membrane 5.

The membrane 5 is also made of a thin and flexible material to allow for movement of the visor 3 relative to the face seal 4 during adjustment of the visor 3 position, and also in order to minimise the bulk of the respirator around the wearer’s face to allow the wearer to, for example, fire a rifle with minimal impediment. The membrane 5 may comprise a fabric layer in one embodiment. It should be appreciated that the thickness of the membrane 5 as shown in the figures, in particular Figures 4 and 5, is exaggerated for ease of reference, although the membrane 5 is thinner than shown.

The respirator 1 includes an inlet valve 29 and an outlet valve 30 to respectively allow air to be brawn into the respirator 1 and its inner mask 2, and to allow air to be expelled out of the inner mask 2 and respirator 1. The inlet valve 29 is formed within an inlet port 31 which includes a coupling mechanism (not shown) to enable a filter cartridge ‘C’ see Figure 3) or a supply of breathable gas to be connected to the inlet port 31. In the embodiment shown in the figures, only one inlet port 31 is shown. However, in alternative embodiments of the respirator of the invention, a plurality of inlet ports 31 may be provided. Such multiple ports 31 may be provided with one on the left side and one on the right side of the respirator 1. This can allow for both left and right handed wearers to fit a filter cartridge or breathable gas supply in a position which will not obstruct use of a weapon. Specifically, it allows the wearer to fit the filter cartridge/breathable gas supply to the opposite side of the respirator 1 to the side of the face they will rest a rifle butt when firing a rifle. Such a respirator may also include a central inlet port 31, for example in the lower front portion of the respirator 31, which would allow for both left and right sided rifle firing by a wearer. The inlet ports 31 may preferably include a sealing element of other inlet port closure mechanism that functions to prevent ingress of ambient air into the respirator 1 when a filter cartridge or supply of breathable gas is not connected to the inlet port 31.

Referring to Figure 6, a cross-sectional view of a portion of the face seal 4 is shown, which illustrates the configuration and construction of the face seal 4. (Note that the configuration of the face seal is not shown in detail in Figures 1 to 3 for the sake of ease of illustration). The face seal 4 is made of rubber, preferably butyl rubber. The face seal 4 includes a first portion and a second portion. The first portion comprises a foot portion 32 and the second portion comprises a flange 33 extending from the foot portion 32. The peripheral edge 6 of the face seal 4 referred to previously is located at a distal end of the flange 33. A stiffening element 34 is embedded within the foot portion 32 and is introduced into the face seal 4 during a moulding operation by placing the stiffening element 34 within a rubber mould for the face seal 4 and forming the rubber of the face seal 4 around the stiffening element 34. The stiffening element 34 maybe made of glass fibre, plastic, metal or other suitable material. The stiffening element is preferably, as shown, a thin strip extending through the face seal 4. This serves to give the face seal 4 structural strength and a degree of rigidity to allow it to sit firmly against and around a wearer’s face. The stiffening element 34 allows for some flexibility but also helps to prevent the front of the respirator 1 distorting when the harness 16 is adjusted and tightened over a wearer’s head. The stiffening element preferably extends around the entire perimeter of the face seal 4. However, the face seal 4 may comprise one or more stiffening elements 34 disposed at spaced locations around the perimeter of the face seal 4.

The foot portion 32 includes an inner seal 35 and an outer seal 36. Both inner and outer seals 35,36 comprise flat lip portions of the face seal 4 which are configured to lie flush against a wearer’s face/head. In use, the inner seal 35 lies within the interior space defined by the respirator 1 and the wearer’s face, and the outer seal 36 lies on the outside of the interior space. The flange 33 extends from the foot portion 32 from a point between the edges of the inner and outer seals 35,36. The flange 33 is closer to being in alignment with the outer seal 36 than with the inner seal 35. That is, the inner seal 35 returns back with respect to the flange 33 and lies adjacent the flange 33, whereas the outer seal 36 continues beyond the flange and extends away from the flange 33. This configuration of face seal 4 advantageously enables the respirator 1 to be used on both a positive pressure mode (e.g. in use with a pressurised supply of breathable gas) and negative pressure mode (e.g. with an filter cartridge attached to the respirator so that air is drawn into the respirator through the filter by wearer inhaling and creating a negative pressure within the respirator), as described below.

For reference, figures 7A and 7B respectively show conventional positive and negative pressure face seals as used in known respirators. The positive pressure face seal 104 of figure 7A includes a return portion 105 and a flange 106 that lies flush against a wearer’s head H. In a positive pressure situation, the pressure Pint of breathable gas supplied to the interior of the respirator is greater that ambient atmospheric pressure Pamb· The interior pressure Pint exerts pressure, shown by arrows P, on the flange 106, forcing the flange 106 into sealing contact with the wearer’s head H to make an airtight seal therewith. However, if this design of face seal 104 is used in a negative pressure respirator such that Pamb is greater than Pint when the wearer inhales, ambient air can be drawn past the face seal 104, as shown by arrows A, due to the tapering configuration of the face seal 104 as seen from the outside. This may allow hazardous ambient atmosphere into the respirator.

Figure 7B shows a negative pressure face seal 204 which includes a flange 206 that lies flush against a wearer’s head H. In a negative pressure situation, the pressure Pint within the interior of the respirator when the wearer inhales is less than ambient atmospheric pressure Pamb- The ambient pressure Pamb exerts pressure, shown by arrows P, on the flange 206, forcing the flange 206 into sealing contact with the wearer’s head H to make an airtight seal therewith. However, if this design of face seal 204 is used in a positive pressure respirator such that Pamb is less than Pint (of the pressure of breathable gas supplied to the interior of the respirator), the supplied breathable air can escape past the face seal 204, as shown by arrows A, due to the tapering configuration of the face seal 204 as seen from the inside. This would cause the breathable gas supply to be wasted and be quickly exhausted, significantly reducing the effective usable time of the respirator.

The face seal 4 of the present invention shown in figure 6 comprises both inner and outer seals 35,36, as described above. Accordingly, the respirator 1 can be used in both a positive pressure mode and negative pressure mode. In a positive pressure mode, the inner seal 35 acts in the manner described above with reference to the face seal 104 shown in figure 7A, to form an effective seal against a wearer’s head. Furthermore, in a negative pressure mode, the outer seal 36 acts in the manner described above with reference to the face seal 204 shown in figure 7B, to form an effective seal against a wearer’s head.

An alternative configuration of face seal 4’ is shown in Figures 8A to 8C and comprises a foot portion 42 and a flange 43 extending from the foot portion 42. A stiffening element 44 is embedded within the foot portion 42 and functions as per the stiffening element 34 of the first embodiment of face seal 4 described above. The foot portion 42 includes an inner seal 45 and an outer seal 46 configured to lie against a wearer’s face/head. In use, the inner seal 45 lies within the interior space defined by the respirator 1 and the wearer’s face, and the outer seal 46 lies on the outside of the interior space. The flange 43 extends from a point between the edges of the inner and outer seals 45,46 of the foot portion 42. A difference over the first embodiment of face seal 4 is that the underside of the foot portion 42 is concave, and the flange 43 is not inclined towards the inner seal 45. The concave foot portion 42 may help to maintain a seal against the wearer’s head H. For example, as the face seal 4’ is pressed against the wearer’s head H, the concave foot portion 42 is deformed to reduce the curvature and expel air from the gap between the wearer’s head and the underside of the foot portion 42. This can be seen in the difference in shape of the foot portion 42 between Figures 8A and 8B. This may create a region of reduced pressure, similar to a suction-cup effect.

The face seal 4’ also advantageously enables the flange 43 to flex about a range of movement relative to the foot portion, as shown by angles Θ in Figures 8B and 8C.

Here, the flange 43 effectively can pivot about a pivot point 47 proximate the point where the flange 43 meets the foot portion 42. This range of movement may help the respirator accommodate different head shapes in different wearers, and also accommodate the different angles the flange 43 will be positioned in at different positions around the face and head of a wearer.

The face seal 4’ of the alternative configuration is also configured to enable the respirator 1 to be used in both a negative and a positive pressure mode since the foot portion 42 has both inner and outer seals 45,46, as explained above.

In use of the respirator 1 of the invention, a wearer loosens the harness 16, and places the respirator 1 over their head, locating the inner mask 2 over the nose and mouth and locating the face seal 4 around the face on the forehead, chin and sides of the face, as shown in Figures 4 and 5. The adjustors 21 are adjusted to ensure the upper, middle and lower harness straps 17,18,19 securely locate and retain the face seal 4 on the wearer’s face. With the face seal 4 secured in position, the connectors 23 are adjusted to ensure the inner mask 4 is securely retained in position over the wearer’s nose and mouth. The inner mask 2 is then securely held in a fixed position on the wearer’s face. The knob 25 is then adjusted to tilt the visor 3 towards the wearer’s eyes until it is as close as possible without risking touching the wearer’s eyes in use. The closeness of the visor 3 ensures that the wearer’s field of view through visor is as wide as possible. This also ensures that, in use, a rifle scope can be brought up to the wearer’s aiming eye to be as close as possible to the eye for minimal inconvenience of using the respirator while operating the weapon. As the visor 3 is adjusted, the thin flexible membrane 5 adjusts and conforms to the differing respirator configuration. Once the respirator is fully adjusted and fitted to the wearer’s head, the thin membrane 5 provides very little bulk to the respirator at the sides of the wearer’s head, and so offers minimal hindrance to aiming a rifle by, for example, bringing the rifle up to the wearer’s line of sight and resting the rifle butt against the wearer’s cheek.

If the respirator 1 is to be used in a negative pressure mode, a filter cartridge is fitted to the inlet port 31. In embodiments with multiple inlet ports 31, the wearer can choose which location to fit the filter cartridge so as to offer minimal obstruction in use. If the respirator is to be used in a positive pressure mode, a supply of pressurised breathable gas can be connected to the, or one of the inlet ports 31.

In one embodiment of the respirator 1 of the invention, the above-described configuration of face seal 4,4’ extends around the entire perimeter of the face seal 4,4’, namely the face seal 4, 4’ including inner and outer seals 35,36,45,46 either side of a flange 33,43. However, in alternative embodiments of respirators falling within the scope of the invention, only certain sections of the face seal 4,4’ may in include such a configuration. In these embodiments, the sections having the configuration shown in Figures 6 and 8A - 8C may comprise the sections at the side of the head from the temples down to the chin, but the sections of face seal 4,4’ may not include such a configuration at the forehead and chin region.

The face seal 4,4’ may include a cup-shaped section to receive a wearer’s chin to help locate and secure the face seal 4,4’ in place on a wearer’s face.

In use, when a wearer breathes in, air is drawn through the filter cartridge or from the source of pressurised breathable air, through the inlet valve 29 and into the inner mask 2. When the wearer exhales, the exhaled air, which obviously has a higher C02 level than the breathed-in air, is exhaled into the inner mask 2 and is vented out of the respirator through the outlet valve 30. The inner mask 2 does not necessarily need to make an fully air-tight seal against the wearer’s face, but simply needs to make an approximate seal to act as a C02 catcher so that the majority of the high-C02 content exhaled air is vented from the interior space of the respirator to prevent C02 build up within the respirator.

Figure 9 shows a portion of an alternative configuration of respirator 1 of the invention. Features in common with the previous embodiments retain the same reference numerals and a detailed description thereof will not be repeated. A difference with the respirator 1 of this alternative configuration is that the height of the inner mask 2 relative to the face seal 4 can be adjusted. This is to provide further adjustability to accommodate difference wearer face shapes, and so allow for different “balance points” of the inner mask 2 on the wearer’s face held thereon by the straps 22.

The ends of the straps 22 remote from the inner mask 2 each include a first fastener 48. The face seal 4 includes a plurality of cooperating, second fasteners 49 arranged in a line vertically along the sides of the face seal 4. The first and second fasteners 48, 49 are detachably connectable to secure the straps 22 to the face seal 4. By selecting which of the second fasteners 49 to connect the first fasteners 48 to, the relative height of the inner mask 2 to the face seal 4 can be selected. The first and second fasteners 48,49 may comprise any known suitable fastening means, such as poppers, clips, pin and hook connectors, etc.

In the embodiments described above, the or each stiffening element 34 is described as being embedded within the face seal 4,4’. However, the invention is not limited to this configuration and, alternatively, the or one or more of the stiffening elements maybe bonded to the face seal 4,4’. Also, the face seal 4,4’ maybe a laminar structure, made of at least two layers of material, and the stiffening element(s) 34 may be sandwiched between the layers of material. The stiffening element may comprise any suitable material which is stiffer that the material from which the face seal 4,4’ is made.

It will be appreciated that the respirator 1 of the invention enables the visor 3 to be adjusted independently of, and relative to, the face seal 4,4’ and the inner mask 2, and thereby the wearer’s face, to enable a wearer to tilt the visor 3 forwards to backwards to position the visor 3 as close to the wearer’s eyes as possible. Also, the inner mask 2 may be adjustable relative to the face seal 4,4’. Accordingly, the respirator 1 is able to be adjusted to suit a wide variety of face shapes and still provide optimum field of view of the wearer with minimum impediment to operating a rifle having a scope or other sighting system needing to be brought into close proximity to the wearer’s eyes and into the wearer’s line of sight.

The tilting mechanism 24 of the visor may include a locking mechanism (not shown) to lock the visor into a chosen angled position.

Although the tilting mechanism 24 is described as comprising a threaded shaft 26 received in threaded aperture 28 in a plate 27, the adjustable tilting mechanism may comprise an alternative arrangement, for example, toothed ratchet maybe formed on or attached to the visor and the inner mask may include a latch member releasably engageable with the teeth of the ratchets to hold the visor 3 in a fixed position relative thereto.

In the above-described embodiments of respirator 1 of the invention, the inner mask 2 is attached to the face seal 4. However, the invention is not intended to be limited to this configuration and, in an alternative embodiment (not shown), the inner mask 2 may be attachable to an alternative fixing point. For example, the straps or wires 22 that extend from the inner mask 2 maybe connectable at their opposite ends to a helmet of an infantry personnel. In such an embodiment, the straps or wires 22 could extend through the flexible membrane 5 that connects the face seal 4 to the visor 3. Holes could be provided in the membrane 5 through which the straps or wires 22 could extend, and an airtight seal, such as a grommet, rubber moulding or other sealant may be provided between the straps or wires 22 and the membrane to ensure the junction between the straps or wires 22 and the membrane 5 is air-tight.

Claims

Claims

1. A respirator comprising an oro-nasal mask configured to surround a wearer’s nose and mouth, a visor pivotably mounted to the oro-nasal mask, a peripheral face seal to surround a wearer’s face, the peripheral face seal comprising a resilient reinforcing element, and a gas-impermeable layer extending between the peripheral face seal and the visor.
2. A respirator according to claim 1 wherein the peripheral face seal comprises an annular member and the resilient reinforcing element is embedded within the annular member.
3. A respirator according to claim 2 wherein the peripheral face seal comprises a moulded annular member and the resilient reinforcing element is embedded within the moulded annular member.
4. A respirator according to claim 2 wherein the peripheral face seal comprises an annular member comprising a laminar structure and the resilient reinforcing element is disposed between two or more layers of the laminar structure.
5. A respirator according to claim 1 wherein the peripheral face seal comprises an annular member and the resilient reinforcing element is bonded to the annular member.
6. A respirator according to any preceding claim wherein the peripheral face seal comprises an annular member and the resilient reinforcing element extends entirely around the annular member.
7. A respirator according to any of claims 1 to 5 wherein the peripheral face seal comprises an annular member and a plurality of spaced resilient reinforcing elements are provided within the annular member.
8. A respirator according to any preceding claim wherein the or each resilient reinforcing element comprises a steel band or bead. 9· A respirator according to any preceding claim wherein the or each resilient reinforcing element comprises a glass fibre reinforced polymer element. to. A respirator according to any preceding claim wherein the oro-nasal mask is connected to the peripheral face seal by at least one strap on each side of the oro-nasal mask.
11. A respirator according to claim 10 wherein each strap is made of an inextensible material.
12. A respirator according to claim 10 or claim n wherein the straps include adjustors to enable the length of the strap between the peripheral face seal and the oro-nasal mask to be adjusted.
13. A respirator according to any of claims 10 to 12 comprising a connection mechanism to secure the straps to the peripheral face seal, wherein the connection mechanism is configured to enable the straps to be secured in a plurality of different positions on the peripheral face seal.
14. A respirator according to claim 13 wherein the connection mechanism comprises a first fastener on each strap and a plurality of second fasteners on each side of the peripheral face seal, wherein the first and second fasteners are engageable to connect the straps to the peripheral face seal.
15. A respirator according to any of claims 1 to 9 wherein the oro-nasal mask includes at least one strap on each side of the oro-nasal mask extending through the gas-impermeable layer and configured to connect the oro-nasal mask to a helmet having cooperating connection elements.
16. A respirator according to claim 15 wherein a seal is provided at the interface where the straps pass through the gas-impermeable layer.
17. A respirator according to any preceding claim wherein the peripheral face seal comprises a first section for contacting the wearer’s face, and a second section extending from the first section, the impermeable layer being bonded to the second section.
18. A respirator according to claim 17 wherein the first section comprises an annular member having first and second peripheral edges, and wherein the second section comprises a flange extending from between the first and second edges.
19. A respirator according to claim 18 wherein the first and second peripheral edges comprise flat lip sections configured to lie flat against a wearer’s face.
20. A respirator according to any of claims 17 to 19 wherein the first section of the peripheral face seal is concave in cross-section in an undeformed state.
21. A respirator according to any preceding claim wherein the gas-impermeable layer extends between the peripheral face seal and the visor around the entire perimeter of the peripheral face seal and visor such that, in use, the oro-nasal mask is contained within a closed space defined by the wearer’s face, the visor, the peripheral face seal and the gas-impermeable layer.
22. A respirator according to any preceding claim comprising an adjustable mounting mechanism connecting the visor to the oro-nasal mask configured such that the angle of the visor relative to the oro-nasal mask can be adjusted.
23. A respirator according to claim 22 wherein the adjustable mounting mechanism includes a locking mechanism to enable the visor to be locked in a selected position relative to the oro-nasal mask.
24. A respirator according to any preceding claim comprising an inlet port for the inlet of breathable air into the respirator, the inlet port including a coupling mechanism for connecting a filter cartridge and/or breathable air supply line to the respirator.
25. A respirator according claim 24 comprising a plurality of inlet ports such that a user can select which location to connect a filter cartridge and/or breathable air supply line to the respirator.
26. A respirator according to claim 25 wherein the inlet ports are provided in at least two locations of a left side of the respirator, a right side of the respirator and a central position on a lower region of the respirator.
27. A respirator according to any preceding claim wherein the peripheral face seal comprises a harness including a plurality of straps to secure the respirator in place on a wearer’s head.
28. A respirator according to any preceding claim wherein the gas-impermeable layer extending between the peripheral face seal and the visor comprises a fabric layer.
29. A respirator substantially as hereinbefore described with reference to the accompanying drawings.