Jan. 27, 1948.
H. w. LINDSAY
`
2,435,181
BREATHING :[NIDICATOHA
- Filed D60. .18, 1945
SL,W/fPoYxUEd/v
1N VEN TOR.
Patented Jan. 27, 1948
„ 2,435,181
ÄUNITED STATES PATENT OFFICE
2,435,181
BREATHING INDICATOR
Harold W. Lindsay, Redwood City, Calif., assign
or to the United States of America, as repre
sented by the Secretary of War
Application December 18, 1945, Serial No. 635,741
'
4 Claims.
(Cl. 177-311)
1
2
The invention described herein may be manu
factured and used by or for the Government c-f
the United States for governmental purposes,
without the payment to me of any royalty
thereon.
This invention relates to breathing indicators
or apparatus which will give some indication at
a remote point that a member of the crew of a
bomber or other large aircraft in _flight is ceas
ing to breathe through his oxygen mask.
On 10 placed by some other visual indicator emitting
no light rays, in the event that the conditions
of the flight necessitate a darkened aircraft, or
numerous occasions during the present war, per
sonnel in aircraft have died of anoxia or an-oxemia or for other causes, without knowledge of
the other members of the crew that they were in
distress. A breathing indicator may save many
lives as effectual measures usually may be taken
_to restore respiration, provided the other mem
bers of the- crew are apprised of the danger in
suñicient time.
an electric lamp IIl is in a circuit including leads
II, I2, I3, and I4, a battery or other current
source I5 and the contacts I6 and I1 which the
switch 9 short circuits when in closed position.
Obviously, if the bellows is moved suñìciently,
switch 9 will close the circuit with each exhala
tion and open it with each inhalation, thus caus
ing signal lamp I0 to light up and go out at cor
responding times. Lamp IU may of course be re
Y
it may be replaced with an aural indicator. f'
Also connected to battery I5 is a circuit in
cluding lead I3, a conductor I8, heating coil i9
and a lead 20 which is connected with lead II
between lamp I8 (or other indicator) and switch
terminal Il. With this arrangement, coil I9 will
carry current whenever the lamp circuit is closed
by switch 9, and thus the coil will be heated in
termittently. A bimetallic arm 2I, which is`one-half of a switch 22, is provided with a contact 23
One of the objects of the invention is to pro
vide apparatus which will give a danger signal
whenever the supply pressure of the oxygen drops,
whether from failure of the supply itself or by
on one end. A conductor 24 connects the bime
disconnection of the oxygen mask. The inven
tallic arm 2I with lead I3, so that current from
tion further aims to provide a breathing indicator 25 the battery is conducted through arm 2l to con
which is of simple construction, which is'light
tact 23. A second bimetallic arm 25, forming the
in weight, occupies little space, is easily installed
other half of switch 22, has a contact 26 on one
and maintained, requires little power, is depend
end, said contact co-operating with contact 23
able, and is readily adaptable for use with oxy
to close a circuit under certain conditions which
gen equipment already standardized for military 30 will be described. A lead 21 is electrically con
and naval service. Other objects Iwill be appar
nected with the second bimetallic arm 25 and is
ent from the following description of a preferred
coupled to -an electric warning or “danger” lamp
embodiment of the invention shown in the ac
28 which may be a red bulb or be behind a red
companying drawing, in which the single figure
shows diagrammatically an arrangement of
parts for indicating at a remote point breathing
and cessation of breathing.
'
Referring particularly to the drawing, an oxy
light-transmitting panel, not shown. A lead 29
couples the other contact of lamp 28 with the
lead I4 on the negative side of the battery. An
aural signal may be operated instead of or in
conjunction with lamp 28. The signal lamps Ill
gen mask I is connected by tubing 2 and a
and 28 may be located at a central station in the
quick-detachable coupling 2a to a standard oxy 40 airplane, in the pilot’s compartment, or wherever
gen demand regulator 3 which in turn is con
nected by tubing 4 to the oxygen supply line 5.
It will be understood that the described ar
A bellows 6, which may be similar to a “Sylphon”
rangement, which is for a single person, will be
bellows, is also coupled at one end to the oxygen
duplicated for each member of the aircraft crew.
demand regulator 3 and is so constructed and 45
Operation
convenient.
' .
arranged that it collapses under atmospheric
As long as normal or rhythmic breathing con
pressure with each breath inhaled, while with
each exhalation it expands, due in part to the
tinues, the bellows-operated switch 9 will close
counterpressure of the exhalation and in part
and open, thus heating the bimetallic strip 2| in
to the action of an internal spring, not shown. 50 termittently to maintain its average temperature
An insulating link 8 is secured at one end to bel
suiiiciently high to sustain an air gap or open
lows 6 and is pivotally connected at its opposite
circuit between the contacts 23, 26, which will
end with a switch 9 to control circuits which
will now be described.
keep the “danger” lamp 28 dark. However, if
respiration weakens, or if the supply pressure
To indicate that the apparatus is functioning, 55 drops or if the oxygen mask is disconnected, the
2,435,181
4
bellows may not close switch 9, and if switch 9
naling means operated by each closing ofk said cir
stays open more than a predetermined time in
terval, which may be 15 seconds, 30 seconds or
any other desired time interval, heating coil I9
will cool to a point where the bimetallic strip 2|
cuit; a second normally open circuit; a thermo
static switch connected to the first circuit to be
energized thereby and constructed and arranged
and 26 together, to close the circuit of the “dan
to automatically couple the second circuit to the
source of power when the current of the first
circuit fails for a »predetermined period; and a
ger” lamp 28. The pilot or other lperson at the
warning signal coupled into the 4second circuit to
will curl toward strip 25, to bring contacts 23
give an indication at a remote point of weak
central station will then give the necessary warn
ing to other crew members over the interphone.
10 breathing or cessation of breathing of the person
`wearing the mask.
Obviously, the bellows must be so constructed
,3. _In combination with an oxygen system in
as to operate well at all temperatures .and at.
cluding a source of supply, an oxygen demand
mospheric pressures which may be encountered
«regulator connected to the source of supply, and
in a night. Also, switch 22 Should be shielded
.an oxygen îmask connected with the oxygen de
and insulated so as to be protected against .ine
mand regulator; a .device movable responsive to
jury and rendered insensitive to sudden and sharp
atmospheric _pressure made effective by inhalation
by the person wearing the oxygen mask, and
movable oppositely responsive in part to counter
in ambient temperature, or in other words, to
maintain the air gap between contacts 23 and 20 pressure from the exhaling lungs of said person;
temperature variations. The second vvbimetallic
strip 25 is provided to compensate for changes
_26 ¿fairly constanteven though‘switch `l22 is sub
a switch mechanically connected »to said device;
jected `to temperature Changes of 100° or more,
and it _may be made manually adjustable (not
shown) vto vary said air gap and may be shield
a >circuit connected ~with a source of electricity
and _said switch, and being so connected and >lil’.
ranged that the switch closes and opens ¿it each
ed (not shown) by insulation from ¿the heat of 25 time the device moves through one cycle respon-f
coil vlil. A master switch (not shown) may also
sive to the normal breathing of said person; a
be employed to keep all circuits open until the
thermal-,responsive switch which is a _part „of said
oxygen mask is adjusted and regular breathing
circuit and is heated electrically whenever -Said
through the oxygen demand regulator is estab
circuit is closed by the ñrst-named switch; a lscc
lished. While the ,apparatus` is described »as 30 ond circuit which is automatically >connected to
though it were exclusively for use with oxygen,
the source of power by the thermal switch when
obviously it ~will operate with any combination
thelatter cools responsive to opening of the ñrst
of breathable gases. Various changes _in the ap
named circuit; and an electricalindicating -device
paratus willoccur to those skilled in the art fand
which _is connected »in the second circuit and is
Iadoonot wish lto be limited to the _particular ar 35 energized when the second circuit is closed..
rangement shown,~except .as .required by the ap
4, In combination with an oxygen supply ¿sys-V
pended claims.
tern including a :source ofoxygen supply, 4arr-oxy
yWhitt V_I Claim ,iSî
een demand regulator connected to the source 'of
~1~ 1.11 an oxygen Warning >system of the char
supply, and an oxygen mask connected with .the
aoter described, in combination, an oxygen supply 40 oxygen demand regulator; a bellows connected
source; ,an oxygen mask; a conduit connecting
the .oxygen mask with the source of supply; a
with the oxygen demand regulator and _so oon
structed and arranged that with every breath
pressure-responsive switch , operatively associated
inhaled and exhaled by the kperson wearing ,the
oxygen mask, the bellows contracts and expands;
withsaid conduit and opening and closing respon
sive to variations in pressure due to consumption ~
a circuit including a source of power, -a switch
of oxygen by the person wearing the mask; an
electric circuit .associated with said switch in
cluding Aa source of electric power, a warning in
and leads; means mechanically connecting the
dicator whichis electrically operated, and a ther
bellows responsive to normal breathing will close
and open said switch; a second normally open cir
cuit including signaling means; and a _device
maldevicewhich is continually being heated >upon 1
closing of Asaid switch; and connections between
thethermal device .and the warning indicator so
constructed :and arranged that cooling of the
thermal device below a certain predetermined
temperature will cause the indicator to show or .
Sound a wor-lling.
12. >In combination with an oxygen supply sys
tem including a source of supply, an oxygen de
bellows with the switch, theparts being so ,con
structed and arranged that >movements of the
which >oportunas upon failure of energization of
the first-named circuit after a predetermined
period to connect the second circuit with a source
of power to‘cause the vsignaling means to kgive
warning of the open circuit condition of the „first
circuit, and hence to warn .of weak breathing ,or
cessation of breathing,
HAROLD W. LINDSAY
mand regulator connected with >the source of supe
ply, and `an oxygen mask connected with the oxy
gen demand regulator; a bellows connected with
the oxygen demand regulator and so constructed
and arranged that with every breath inhaled and
REFERENCES yCITED
vThe following »references >are of record .in the
ñle of this patent:
exhaled by the person wearing the mask, thebcl
lows contracts and expands; a circuit including 65
a source of power, leads and a switch connected
with the leads; means mechanically connecting
the :bellows with the switch so that movements
of the bellows responsive to normal breathing of
said :person will close and open said switch; sig 7
'
UNITED STATES PATENTS
Number
Name
Date
51,134,320
Drew ______________ __ Apr. 6, -191‘5
V.2,087,598
Hebler __-__, ______ __ July 20, v193'7
2,193,945
Strauss et al. ____ __ Mar. AV19, 1940
¿324,424
APollack _____....____... July 13, >1943