Exhalation valve means of a respiration mask

An exhalation valve means of a positive pressure type respiration mask which can be easily converted to a non-positive pressure type (atmospheric pressure type) mask when necessary. The exhalation valve means includes a valve body unit, which comprises an exhalation value seat, a valve body supporting member which is detachably mounted within an exhalation valve chamber, and a valve body which is supported by said valve body supporting member and energized against said exhalation valve seat. Said valve seat has a means for mounting a rubber membrane valve body which is used for the valve body unit.

FIELD OF THE INVENTION 
This invention relates to a respiration mask and in particular, to an 
exhalation valve means of a respirator having a mask body which covers the 
whole face of a wearer and a valve body unit used in such an exhalation 
valve means. 
DESCRIPTION OF THE PRIOR ART 
Respiration masks have two types, one of which is a positive pressure type 
which has, as an exhalation valve means (exhaust valve means), a valve 
means having a valve body which is energized toward the closed position by 
a spring and which in use the interior of the mask is always maintained 
under a pressure above atmospheric pressure i.e. under positive pressure, 
and the other of which is a nonpositive pressure type which has a valve 
means having a rubber membrane valve body which is fixed at its center on 
a valve seat body and is in close contact at its peripheral portion with a 
valve seat due to its own elasticity. Although the difference between the 
both is only in the construction of the exhalation valve means, the 
respiration masks of the positive pressure type and the non-positive 
pressure type have so far been manufactured, bought and used as quite 
different masks. 
SUMMARY OF THE INVENTION 
The object of the present invention is to eliminate the uselessness that 
the respiration masks of the two types are manufactured, bought and used 
as different masks, though the difference is only in the construction of 
the exhalation valve means. That is, the object of the present invention 
is to provide a mask which can be converted for use to a non-positive 
pressure type mask or a positive pressure type mask when necessary, and a 
valve body unit which can convert a non-positive pressure type mask known 
or currently in use to a positive pressure type mask. 
Thus, according to the present invention, the user who uses exchangingly 
both the positive pressure type and non-positive pressure type masks will 
no longer be necessary to buy and keep the two kinds of masks. Further, 
according to the present invention, a person who already has a known 
non-positive pressure type mask can alter it to a positive pressure type 
mask by buying only a valve body unit according to the present invention. 
The characteristic feature of the present invention lies in a construction 
of an exhalation valve means of a respiration mask, wherein a valve body 
unit is disposed in an exhalation valve chamber, said unit consisting of a 
valve body supporting member which is detachably and firmly mounted in the 
exhalation valve chamber by a suitable means, a valve body which is 
supported by said valve body supporting member and movable to a position 
where it is brought into contact with said valve seat or to a position 
where it is separated away from said valve seat, and means which energizes 
said valve body against said valve seat under a desired pressing force, 
and said valve seat is provided approximately at its center with a 
mounting portion for a membrane valve body which is used when converting 
the respirator to the non-positive pressure type. 
Another characteristic feature of the present invention lies in a 
construction of an exhalation valve of a respiration mask, wherein a valve 
body unit is disposed in an exhalation valve chamber, said unit consisting 
of a valve body supporting member which is detachably and firmly mounted 
in the exhalation valve chamber by a plurality of leg pieces being in 
contact with the inner surface of the side walls of the exhalation valve 
chamber, a valve body which is supported by said valve body supporting 
member and movable to a position where it is brought into contact with 
said valve seat or to a position where it is separated away from said 
valve seat, and means which energizes said valve body against said valve 
seat under a desired pressing force, and said valve seat is provided 
approximately at its center with a mounting portion for a membrane valve 
body which is used when converting the respirator to the non-positive 
pressure type. 
A further characteristic feature of the present invention resides in a 
valve body unit which consists of a valve body supporting member which is 
to be detachably and firmly mounted in the exhalation valve chamber by a 
plurality of leg pieces being contacted with the inner surface of the side 
walls of the exhalation valve chamber, a valve body which is supported by 
said valve body supporting member and movable to a position where it is 
brought into contact with said valve seat or to a position where it is 
separated away from said valve seat, and means which energize said valve 
body against said valve seat under a desired pressing force. 
For further understanding of the invention the invention will now be 
described more in detail by way of a preferred embodiment with reference 
to the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIGS. 1 to 3, reference numeral 1 designates a respiration air 
chamber. The respiration air chamber comprises an inhalation air duct 
receiving opening 3, an exhalation valve chamber 5, and a portion 7 for 
fitting a speaking diaphragm or a speaking membrane. The exhalation valve 
chamber 5 is provided with an exhalation valve seat body 9 which 
constitutes a bottom of the chamber, and a valve body supporting member 15 
that is detachably and firmly mounted by four supporting legs 11, 12, 13 
and 14 which are inscribed to the angle portions of the side walls of said 
exhalation valve chamber 5 which forms approximately a hexagon. A bearing 
cylinder 17 is provided at the center of the valve body supporting member 
15, and a cylindrical valve stem 21 projecting from the center of a valve 
body 19 is slidably fitted in the bearing cylinder 17 (see FIG. 2). A coil 
spring 23, which presses the valve body against the exhalation valve seat 
and surrounds the bearing cylinder 17 and the valve stem 21, is arranged 
between the valve body supporting member 15 and the valve body 19. The 
strength of said coil spring 23 is selected to be responsive to the 
positive pressure within the respiration mask. Additionally, in FIGS. 1 to 
3, reference numeral 25 designates an exhalation valve cover, reference 27 
a stopping projection for the exhalation valve cover 25, and reference 29 
a mask body of rubber. 
Referring to FIGS. 4 to 7, the bearing cylinder 17 is connected to a ring 
body 35 which surrounds the cylinder 17, through three connecting arms 31, 
32 and 33 which are circumferentially spaced apart from each other and are 
extending radially outward from the outer periphery of the cylinder 17. 
Four supporting arms 36, 37, 38 and 39 extend radially outward while 
mutually spacing from the ring body 35 and the respective supporting arms 
36, 37, 38 and 39 are provided at their outer ends with the supporting 
legs 11, 12, 13 and 14 approximately at right angles with said arms. A row 
of grooves which are formed in the inner peripheral surface of the bearing 
cylinder 17 and axially extend mutually in parallel are to reduce 
friction. The bearing cylinder 17, the connecting arms 31 to 33, the ring 
body 35, the supporting arms 36 to 39, and the supporting legs 11 to 14 
are formed in one body. The valve body supporting member 15 is usually 
constructed in such a manner that it may be retained in its mounting 
position even by the exhalation valve cover 25. In the drawings, reference 
numeral 10 designates a stub of the exhalation valve seat body 9, which is 
used for mounting a membrane valve body used when converting the 
respirator to the non-positive pressure type, and reference numeral 16 
designates a friction tube of rubber or the like, which is fitted onto the 
supporting legs 11 to 14 of the valve body supporting member 15 for 
increasing the engaging friction. In the embodiment abovementioned, the 
mounting means for the membrane valve body is the stub 10, but in case the 
membrane valve body is of umbrella shape having a mounting stem, the 
exhalation valve seat body 9 is provided with an opening which receives 
and retains the stem of the membrane valve body, instead of the stub 10. 
Although, in the above-mentioned embodiment, the valve body supported by 
the valve body supporting member is energized toward the valve seat by the 
coil spring, it will be also all right if the valve body may be energized 
by magnetic force instead of by the coil spring. 
In the above-mentioned embodiment, the present invention has been described 
with reference to a exhalation valve chamber which constitutes part of the 
respiration air chamber, but the present invention can naturally be 
applied also to an independent, separate exhalation valve chamber. 
While there has been described a preferred form of the invention herein, 
modifications and variations are obviously possible in the light of the 
above teachings. It is therefore to be understood within the scope of the 
appended claims that the invention may be practiced otherwise than as 
specifically described above.