MOLDED NOSECUP VALVE ASSEMBLY

Abstract: In a gas mask, a flexible nosecup is used to prevent humid air that is exhaled from contacting the eye pieces of the mask. The nosecup is equipped with a one-way valve to allow fresh air into the nosecup. The conventional rigid valve body attached to the nosecup is replaced with a valve body (44) molded integrally with the material of the nosecup and a valving element (54) with a concave disk (56) having its rim (60) seated on the annular valve seat (52) of the valve body (44).

Description: MOLDED NOSECUP VALVE ASSEMBLY FIELD OF THE PRESENT INVENTION The present invention relates to gas masks an more particularly to the one-way valves used in th nosecups of gas masks. BACKGROUND In a gas mask, a nosecup is used to preven humid air that is exhaled from contacting the eye piece of the mask and causing fogging problems. A one-wa valve is required in the nosecup to allow fresh air in Current gas masks use a rigid metal valve body crimpe onto a hole in the nosecup or a rigid plastic valve bod glued into place in a hole in the nosecup. The valvin element used with either body is a flat, resilient dis sealing on a flat valve seat on the body. With the currently used constructions, th valve body must be produced as a separate item and the assembled into the nosecup. The present invention aim at the ' provision of a valve that is simpler and les expensive to produce. SUMMARY According to the present invention there i provided a valve for a flexible nosecup of a gas mask, said valve comprising a valvε body moulded integrall with the nosecup and including a peripheral valve seat substantially thicker than the nosecup, a resilient valving element with a concave configuration and a rim engaging the peripheral seat, and valve mounting means mounting the valving element on the valve seat, and resiliently deforming a centre portion of the valving element towards the valve seat. By using an integrally molded valve body, the number of parts and cost of production of the valves are significantly reduced. The rubber valve body is .con¬ figured such that it is relatively rigid compared to the thin wall of the nosecup. Consequently, distortions of the nosecup when it is worn on the face will result primarily in a deflection or distortion of the thin wall of the nosecup itself rather than of the valve body. In the event that the valve body is flexed slightly, the distortion is accommodated by the concave, resiliently deformed valving element without losing the sealing capability of the valve on the valve body. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings, which ' illustrate a prior art of the valve in an exemplary embodiment of the present invention: Figure 1 is a side elevation of a gas mask nosecup, partially broken away to show the valve; Figure 2 is a front elevation of a prior ar valve body; Figure 3 is a cross-section of a prior ar valve; Figure 4 is a front elevation of a valve bod according to the present invention; Figure 5 is a sectional, exploded view of valve according to the present invention; Figure 6 is a sectional view of the valve o Figure 5; Figure 7 is a view like Figure 6 with the valv body flexed; and Figure 8 is a view like Figure 7 with the valv body flexed in a double curve. DETAILED DESCRIPTION Referring to the accompanying drawings, Figur 1 illustrates a nosecup 10 that is, in use, locate within -and assembled to a gas mask face piece. Th nosecup has an exhaust opening 12 and an inlet valve 14. A typical prior art inlet valve 14 is illus trated in Figures 2 and 3. The valve consists of a rigi thermoplastic valve body 16 in the form of an annula channel 18. Located centrally within the body 16 is hub 20 joined to the channel 18 by four spokes 22. The hub 20 is in the form of a collar with a central bore 24. The nosecup is made from a flexible sheet rubber 28. It is made with a hole into which the valve body 16 fits, with the edge of the hole seated in the annular channel 18 and secured to the valve body by an appropriate adhesive (not illustrated) . On the inner side of the annular channel 18 is an annular rib 30 that serves as a valve seat for a valving element 32. The valving element includes a flat, resilient disk 34 and a stem 36 projecting from the centre of the disk. Part way along its length, the stem has a head 38 with a tapered leading face 40. Between the head and the disk, the stem has a seat 42 of smaller diameter than the maximum diameter of the tapered face 40. The valving element is installed on the valve body by pressing the stem through the bore 24 through the hub 20, resiliently compressing the head 38 until it has passed through the hub and has expanded on the opposite side. In use, air may pass from the outside of the nosecup, between the seat 30 and the resilient disk 34, when the wearer inhales. On exhalation, the disk 34 is forced against the seat 30 to prevent moist air - from passing from the noseup into the facepiece. The prior art valve with a metal body is simi¬ lar to that Illustrated in Figures 2 and 3, but with the metal body crimped onto the flexible sheet material 28 of the nosecup. An embodiment of the present invention is Illustrated in Figures 4 through 8. As shown more parti¬ cularly in Figures 4 and . 5, the valve of the present Invention includes an annular valve body 44 of molded rubber material with a central hub 46 joined to the valve body by three spokes 48. The valve body 44 is integrally molded with the flexible sheet material 50 of the nose¬ cup, but it is significantly thicker than the material 50 so as to be substantially more rigid. One side of the valve body 44 provides an annular valve seat 52 for engagement with a valving element 54. The valving element 54 has a concave head 56 with a flat, circular central panel 58 surrounded by an annular rim 60 flaring from the periphery of the centre panel 58 towards the valve seat 52. A stem 62 projects from the centre of the panel 58. It includes a head 64 with a tapered face 66 and a seat 68, all of which cor¬ respond to the comparable components of the stem of the prior art valve. The assembled condition of the valve is illus¬ trated in Figures 6, 7 and 8. As shown in Figure 6, when the valve is assembled, the centre panel 58 is deformed to a dished shape by the engagement of the edge of rim 60 with the valve seat 52. This provides a biasing force engaging the valving element on the valve seat. As discussed in the foregoing, the flexible sheet material 50 on the nosecup is considerably more I flexible than the valve body 44 with its thicker cross- section. Consequently, most flexing of the nosecup will occur in the material 50 because it is the main body of the nosecup. However, it is possible that the rubber valve body will deform as illustrated in Figures 7 and 8. In that case, the pre-stresε induced in the valving element 54 by the dishing of the centre panel 58 will bias the rim 60 towards the valve body 44 and keep the edge of the rim 60 in sealing contact with the valve seat 52. Figure 7 illustrates a situation where the valve body 44 is bowed away from the valving element 54, while Figure 8 illustrates an arrangement where the valve body 44 has a double curvature. As shown, in both cases, the rim 60 remains in sealing contact with the valve seat 52. While one embodiment of the present invention has been described in the foregoing, it to be understood that other embodiments are possible within the scope of the invention. The invention is to be considered limited solely by the scope of the appended claims.

Claims: CLAIMS : 1. A valve for a flexible nosecup of a gas mask, said valve comprising a valve body molded integrally with the nosecup and including a peripheral valve seat substantially thicker than the nosecup, a resilient valving element with a concave configuration and a rim engaging the peripheral seat, and valve mounting means mounting the valving element on the valve seat, and resiliently deforming a centre portion of the valving element towards the valve seat. 2. A valve according to Claim 1 wherein the valve seat is substantially circular. 3. A valve according to Claim 2 wherein the valve body includes a hub located within the peripheral valve seat and a plurality of spokes securing the hub to the seat. 4. A valve according to Claim 3 wherein the valv¬ ing element comprises a rim portion surrounding the centre portion and projecting therefrom towards the valve seat. 5. A valve according to Claim 4 wherein the valv¬ ing element centre portion is substantially flat and circular in a relaxed state. 6. A valve according to Claim 5 wherein the valve securing means deform the centre portion of the valvin element to a dished shape. 7. A valve according to Claim 6 wherein the secur ing means comprise a stem projecting from the centr portion of the valving element and stem engaging means o the valve body. 8. A valve according to Claim 7 wherein the ste engaging means comprise a hub located centrally withi the valve seat. 9. A valve according to Claim 8 wherein the hu comprises a collar in which the stem engages. 10.- A valve according to Claim 9 including spokes securing the hub to the valve seat. 11. A valve for a gas mask nosecup molded as flexible, resilient sheet material, said valve comprisin a valve body molded integrally with the nosecup an including an annular valve seat substantially thicke than the sheet material, a hub concentric with the valve seat and a plurality of spokes joining the hub to the valve seat, a resilient valving element including circular centre panel and a substantially frusto-conical rim around the centre panel engaging the valve seat, an a valve stem secured to the centre of the centre panel and to the hub and resiliently deforming the centre panel to a concave configuration to bias the rim into engage¬ ment with the valve seat.

Inventors: DAVIS RONALD E, HARRISON BRIAN H, DAVIS, RONALD, E., HARRISON, BRIAN, H.
Applicants: HER MAJESTY THE QUEEN AS REPRE, HER MAJESTY THE QUEEN AS REPRESENTED BY THE MINIST
Application year: 1990
Main classification: A62B18
IPC codes: A62B18, F16K15