Abstract The invention relates to a combined safety helmet and breathing apparatus and recognises the inherent problem with all such prior art combinations, that the wearer is totally dependent on the breathing apparatus for breathable air for the whole of the time the helmet is in use. The present invention proposes overcoming this problem by providing an air passage (29, or 48) which, when open, connects the breathable volume in the helmet with the surrounding atmosphere and which air passage (29, or 48)is closeable by a valve member (30, or 49) to prevent contamination of the breathable volume by the surrounding atmosphere via the said air passage (29, or 48) when the breathing apparatus is in use. The air passage (29, or 48) and its associated valve member (30, or 49) may be independent of, or incorporated into, the exhalation valve (41 to 47) for venting spent air to the surrounding atmosphere when the breathing apparatus is in use.
1 A combined safety helmet and breathing apparatus, the helmet defining a breathable volume supplied with breathable air by the breathing apparatus and including an exhalation valve for venting spent air to the surrounding atmosphere, characterised in that the helmet includes an air passage connecting the said breathable volume with the surrounding atmosphere and valve means for opening and closing said air passage.
Claim 2
Dependent Claim
63 words
1 A combined safety helmet and breathing apparatus, the helmet defining a breathable volume supplied with breathable air by the breathing apparatus and including an exhalation valve for venting spent air to the surrounding atmosphere, characterised in that the helmet includes an air passage connecting the said breathable volume with the surrounding atmosphere and valve means for opening and closing said air passage.
Claim 3
Dependent Claim
56 words
2 A combined safety helmet and breathing apparatus according to claim 1, characterised in that the valve means is in the field of view of a person wearing the helmet and the valve means includes different visual presentations, in the field of view of the wearer, for the open and closed positions for said valve means.
Claim 4
Dependent Claim
31 words
3 A combined safety helmet and breathing apparatus according to claim 1 or 2 characterised in that said air passage and its associated valve means are independent of the exhalation valve.
Claim 5
Dependent Claim
53 words
4 A combined safety helmet and breathing apparatus according to claims 1 or 2 characterised in that the exhalation valve assembly includes the said air passage and a valve member displaceable between a first position, in which it closes said air passage, and a second position in which it opens said air passage.
Claim 6
Dependent Claim
77 words
5 A combined safety helmet and breathing apparatus according to claim 4 characterised in that the exhalation valve comprising one-way exhalation valve elements are substantially concentric with a central axis for said valve, a plurality of said air passages are equi-spaced about a pitch circle generally concentric with said central axis for the exhalation valve and said plurality of said air passages are opened and closed by a common valve element generally concentric with said central axis.
Claim 7
Dependent Claim
40 words
6 A combined safety helmet and breathing apparatus according to claim 5 characterised in that the said common valve element is displaceable in the direction of said central axis between its positions defining the air passageways open and closed conditions.
Claim 8
Dependent Claim
40 words
7 A combined safety helmet and breathing apparatus according to any preceding claim characterised in that the, or a, said air passage includes means to emit an audible warning when said air passage is open and air is passing therethrough.
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