U.S. patent number 3,762,407 [Application Number 05/247,107] was granted by the patent office on 1973-10-02 for survival support device.
Invention is credited to David E. Shonerd.
United States Patent |
3,762,407 |
Shonerd |
October 2, 1973 |
SURVIVAL SUPPORT DEVICE
Abstract
Apparatus for providing a breathable gas to an individual in an
emergency situation is provided in practice of this invention. The
apparatus contains a breathable mixture of gas for a prolonged
period and, when actuated, provides about 10 minutes of gas to the
user. The gas is contained at high pressure in a lightweight long
tube coiled about a combined fill valve, pressure regulator, flow
control, pressure gauge, and actuation mechanism. This assembly is
in a canister and actuated by perforating a pressure containing
diaphragm between the gas storage reservoir and the pressure
regulator. The canister is connected to the back of a plastic hood
that is fittable over a user's head so that the canister is
arranged during use at the nape of the user's neck so as not to
interfere with any emergency operations and, for example, to permit
the user to wear a helmet or the like. Gas from the canister passes
into the hood at a substantially constant rate and is vented as
required through a check valve. An elastic band around the person's
neck limits leakage.
Inventors: |
Shonerd; David E. (Santa
Barbara, CA) |
Family
ID: |
22933582 |
Appl.
No.: |
05/247,107 |
Filed: |
April 24, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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141781 |
May 10, 1971 |
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Current U.S.
Class: |
128/201.23;
128/205.21 |
Current CPC
Class: |
A62B
17/04 (20130101); A62B 7/02 (20130101) |
Current International
Class: |
A62B
17/04 (20060101); A62B 17/00 (20060101); A62B
7/00 (20060101); A62B 7/02 (20060101); A61m
015/00 () |
Field of
Search: |
;128/142.3,142.7
;222/5 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Recla; Henry J.
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This is a division, of application Ser. No. 141,781, filed May 10,
1971.
Claims
What is claimed is:
1. In a survival support device comprising:
a substantially impervious flexible bag sufficiently large to fit
over a user's head and including a transparent portion adjacent at
least a front part of the bag;
means for permitting gas flow out of the bag and inhibiting gas
flow into the bag;
a hollow coil of high pressure tubing for containing a breathable
gas at high pressure;
regulator means within the coil for maintaining a substantially
contanst outlet pressure over a broad range of inlet pressures and
a substantially constant flow from the outlet thereof;
actuator means within the coil for substantially instantly
connecting the regulator means to the reservoir means;
means for supporting the coil from the bag at a rear portion
thereof against the nape of a user's neck, the improvement
wherein,
the coil of high pressure tubing comprises at least an outer
quadrilateral coil around the regulator means and actuator means
which are substantially rectangular in shape; and
an inner quadrilateral coil substantially concentric with the outer
coil and closely conforming to the shape of the regulator means and
actuator means whereby the total volume of the gas supply is
minimized.
2. In a survival support device as defined in claim 1 the further
improvement comprising:
a diaphragm between the reservoir means and the regulator means,
capable of withstanding a substantial pressure there-across;
a plunger having a perforating tip adjacent the diaphragm;
means for mounting the plunger for movement towards the diaphragm a
sufficient distance that the perforating tip can penetrate the
diaphragm;
means for biasing the plunger towards the diaphragm; and
a removable retaining pin for temporarily holding the plunger away
from the diaphragm.
3. In a survival support device as defined in claim 1 the further
improvement comprising:
a pressure gauge in communication with the coil of tubing;
a pressure containing fill valve in communication with the coil of
tubing; and wherein
the pressure gauge, the fill valve, and the actuator means are all
accessible from the ends of the hollow cylinder.
4. In a survival support device as defined in claim 1 the further
improvement wherein the transparent portion of the bag is flexible.
Description
BACKGROUND
Many situations put personnel in a temporary situation where
breathing of the ambient environment is not practical. A typical
situation of this sort occurs in shipboard fires where heavy smoke
may be produced and effectively trapped in comparatments within the
ship. Personnel within these compartments must evacuate immediately
or face suffocation or severe smoke inhalation injury. When these
personnel are deep within a ship, rapid exiting from the damaged
and smoke-filled area may be virtually impossible in sufficient
time to prevent suffocation or severe injury. It may also be
desirable for personnel to remain at their stations for a limited
period in order to perform various emergency tasks before
evacuation. It may also be important that personnel rescue injured
or incapacitated people within the affected area and, therefore,
they must perform a moderate amount of heavy work during the time
that the environment is not breathable.
Although but one example of an acute situation requiring auxiliary
breathing apparatus has been mentioned, many other such situations
will be apparent, such as various industrial environments where
noxious chemicals may be present, or in ordinary police and fire
work where smoke or noxious chemicals may be encountered without a
significant amount of advance warning.
When there is advance warning of a requirement for auxiliary
breathing apparatus, a variety of conventional equipment is
available for self-contained breathing. A more difficult situation
arises, however, where the emergency may occur without substantial
prior notice, and personnel are required to operate in the
potentially hazardous environment substantially continuously.
Again, referring to a shipboard situation, personnel may work in an
engine room or the like for months or years without encountering a
dangerous situation wherein auxiliary breathing apparatus is
required. When such a situation does occur, however, it is too late
to rely on conventional auxiliary breathing equipment, which may be
located at fixed stations in the vicinity.
It is, therefore, desirable to provide an emergency breathing
apparatus which provides breathing support for survival of
personnel who may be unexpectedly thrust into an emergency
situation wherein the ambient environment is unbreathable. Such a
survival support device should be lightweight and small volume so
that it can be carried or worn by a person substantially
continuously during their normal tasks so that is is always at hand
when required. It should also have high reliability for long
periods of time, substantially complete safety, be confortable to
wear, and rapidly usable after prolonged storage.
BRIEF SUMMARY OF THE INVENTION
Therefore, in practice of this invention according to a presently
preferred embodiment, there is provided a survival support deivce
including a plastic bag fittable over a person's head for excluding
the external atmosphere, a check valve for permitting exhalation,
and a pressurized supply of breathable gas connected to the bag in
position for wearing at the nape of a user's neck.
Preferably, the survival support device stores high pressure gas in
an elongated tube protected by a surrounding canister and wound
about a mechanism that permits long-term storage and instant
actuation, as well as flow control for feeding the breathable gas
into the plastic bag. Preferably, the mechanism includes a filling
vlave, a pressure gauge, and pressure and flow regulators for gas
measurement and control. Actuation and over-pressure protection are
provided by a rupturable diaphragm and diaphragm perforating
mechanism.
DRAWINGS
These and other features and advantages of the invention will be
appreciated as the same becomes better understood by reference to
the following detailed description of presently preferred
embodiments when considered in connection with the accompanying
drawings wherein:
FIG. 1 illustrates a survival support device constructed according
to principles of this invention in typical use;
FIG. 2 is a rear view of the hood portion of the device of FIG.
1;
FIG. 3 illustrates in cutaway perspective a pressurized gas storage
and control system connectable to the hood of FIG. 2;
FIG. 4 illustrates in perspective a control mechanism for the
system of FIG. 3;
FIG. 5 is a cross section through the control mechanism of FIG.
4;
FIG. 6 illustrates in perspective detail of a diaphragm perforating
plunger from the mechanism of FIG. 5;
FIG. 7 is an end view of the plunger of FIG. 6;
FIG. 8 is a rear view of another embodiment of survival support
device constructed according to principles of this invention;
FIG. 9 is an end view of the gas storage and control system of the
embodiment of FIG. 8; and
FIG. 10 is a side view, partly cut away, of the system of FIG.
9.
FIG. 11 is a longitudinal cross-sectional view of a tool used for
filling the reservoir.
Throughout the drawings, like numerals refer to like parts.
DESCRIPTION
FIG. 1 illustrates a typical survival support device as one
embodiment constructed according to principles of this invention.
Modifications of the device illustrated in FIG. 1 are set forth
hereinafter and adaptation to the components illustrated in FIG. 1
will be apparent. Thus, as illustrated in the embodiment of FIG. 1,
a user 11 of the survival support device has a hood 12 pulled over
his head so that a breathable atmosphere can be provided within the
hood.
In the illustrated arrangement, the hood 12 is made of two
essentially flat pieces of plastic that are heat or otherwise
bonded together to form a sack-like structure, the opening of which
is encompassed by an elastic band 13 which during use fits about
the user's neck to provide some degree of gas sealing. The front
portion 14 of the hood 12 is formed of a transparent plastic so
that the user can see through substantially the entire area and
find his way out of a dangerous situation or perform useful tasks
while still in the environment. The rear portion 16 of the hood
need not be transparent, and is typically an opaque plastic sheet
so as to be readily distinguishable from the front portion. In
addition, a greater variety of mechanical properties are available
in opaque or translucent plastics than in transparent materials,
and the structural requirements of the survival support device may
be more readily accommodated by employing an opaque or translucent
material for the rear portion 16 of the hood. The sack-like hood
fits loosely over the head of the user so that he can continue to
wear eyeglasses or the like while using the device.
In the center front of the hood, a conventional check valve 17 is
mounted so as to permit gas to be discharged from the interior of
the hood to the exterior and inhibit reverse flow of gas. The check
valve can be located in other portions of the hood; however, it is
preferred that the valve be located in a region close to the user's
nose or mouth in order to best assure circulation of fresh air or
other breathable gas into this region of the hood.
A gas canister 18, described in greater detail hereinafter, is
connected to the rear portion 16 of the hood by fabric straps 19
(see also FIG. 2), which are buckled or otherwise fastened around
the canister through metal loops 20 (FIG. 3) extending from its
cylindrical surface. The straps 19 are integral with a fabric sheet
21 in the center back of the hood. The sheet is preferably
adhesively bonded to the plastic back portion of the hood or it can
be stitched to a fabric insert (not shown) on the inside of the
hood for greater strength. The canister 18 is thus connected in
close proximity to the rear portion of the hood near its lower edge
so as to lie on the nape of the neck of the user during operation.
By so positioning the gas canister 18, the user's hands and arms
are completely free and unconstrained; he can easily turn his head
in any desired direction without significant hindrance; his view of
the surroundings is not obscured; and he can perform various
required tasks without problems due to the presence of the
canister. The position of the canister at the nape of the neck
further enables the user to go bareheaded or wear a battle helmet,
fire helmet or the like, as desired. Since the gas reservoir is
directly connected to the hood, there is no danger of catching a
tube on surrounding objects and cutting off the supply of
breathable gas, as would be the case if the canister were to remain
at a person's waist or the like.
During normal situations, that is, in the absence of an emergency,
the flexible hood 12 is preferably wrapped around the canister 18
or folded on one side of it to form a cylindrical package
substantially the same size as the canister. This is preferably
stored in a protective plastic bag or the like (not shown), which
may be provided with a rip-open panel or seam, so that access to
the survival support device is rapidly obtained in case of an
emergency. The plastic bag with the canister inside is then
conveniently carried on the user's belt or some other convenient
location until such time as it is needed. It will be clear, of
course, that such survival support devices can also be provided at
fixed locations in a region that may be subject to emergency
situations rather than actually be carried by the personnel at all
times. It is apparent, of course, that when it is carried directly
on the person, the access to the survival support device is most
reliable and quickest.
When it is desired to use the survival support device, it is
removed from its protective container or bag (not shown) if
employed, and the mask or hood 12 is unfolded from the canister 18.
After starting the flow of breathable gas into the hood in a manner
hereinafter described in greater detail, the person donning the
hood merely dips his head forward so as to catch the front portion
of the elastic neck band 13 under his chin. He then pulls the rear
portion of the elastic neck band forwardly and upwardly across his
face and over the top of his head, stretching it as much as
required to do so. Such an operation also swings the gas canister
18 over the top of his head so as to lie in position at the nape of
his neck. The elastic band 13 closes about the person's neck so
that the open end of the bag is closed to provide a degree of gas
sealing. The position of the transparent front portion 14 of the
hood can then be adjusted, if needed, by shifting the entire
canister from side to side, or by grasping the sides of the hood to
twist it into position, or by grasping the check valve 17 in order
to center it adjacent the user's nose or mouth.
Meanwhile, fresh breathable gas is flowing into the hood, as
hereinafter described, so that any noxious gases caught in the hood
during the donning sequence are displaced through the check valve
17. The entire conning sequence and the purge of any remaining
noxious materials within the mask are typically accomplished in
less than about 20 seconds. Flow of breathable gas continues into
the hood from the gas canister, and the person using the survival
support device breathes in a normal manner with inhaled air being
replaced by fresh breathable gas and exhalations largely expelled
through the check valve. The volume of gas entering the hood is
sufficient for the person to perform strenuous work for a period of
at least ten minutes, such as may be required for escape from a
hazardous situation. This may also permit sufficient time for
performing emergency tasks or rescuing other personnel in the
hazardous area. It will also be noted that two persons can share
one survival support device by breathing from the open neck portion
in turns, or a second person can breath gas from the check valve
while being rescued.
FIG. 3 illustrates in cutaway perspective a gas storage canister 18
as illustrated in FIG. 1. As illustrated in this embodiment, the
canister is formed of two substantially similar cup-shaped halves
23, one of which may be flared outwardly slightly and the other
rolled inwardly at their adjoining edges so as to remain centered
when fitted together. In a typical embodiment, the canister is only
51/2 inches diameter and 6 inches long. Mounted within the canister
18 is a double helical coil of high pressure steel tubing 22 within
which gas up to about 5,000 psi may be stored. The elongated tube
for storing high pressure gas is particularly advantageous, since
it is capable of storing a reasonable volume of high pressure gas
without a significant total weight. Thus, for example, a survival
support device providing ten minutes or more of breathable gas can
readily be made with a total weight of only about 31/2 pounds. The
tube for gas storage has other advantages, such as, for example, in
case of a leak as might occur from damage or perforation of the
tubing, the gas tends to leak relatively slowly as compared with a
single cylinder so that no substantially jetting action is caused
by the escaping gas.
The tubing 22 can also be made ductile while still being capable of
supporting the high pressure gases, so that fragments and shrapnel
are not produced in case of severe damage to the tubing. This
latter property is evidenced by a test where a survival support
device was perforated by a 0.308 caliber bullet fired transverse to
the axis of the canister and which ruptured six coils of the high
pressure tubing. The perforated canister rolled off its supporting
six-in-wide shelf and fell to the ground without any noticeable
lateral movement. There was no gas discharge sound discernible from
30 yards away, and no visible evidence of blast or jet propulsion.
Gas which had originally been stored at 5,000 psi could be heard
exiting from the tubing when observers reached the survival support
device 40 seconds after perforation. The rigid canister surrounding
the tubing gas reservoir may also help in minimizing jetting action
in case of tube perforation since gas pressure should never build
to substantial levels in the canister even when there is severe
leakage from the tubing. The canister also helps inhibit shrapnel
in case of damage, as well as preventing damage except in extreme
situations.
The tubing 22 forming the gas storage reservoir is supported away
from one end of the canister 18 by a supporting clamp 25, the ends
of which engage the double helix of tubing and the center of which
is connected to a control mechanism 26 mounted concentric with the
coil of tubing for most efficient packing density. As seen in FIG.
3, the center of the clamp is between a nut 27 and a gas fitting 28
on the end of a pressure regulator 29, described in greater detail
hereinafter. The gas fitting 28 is also connected to the center of
one of the end cups 23 of the canister 18 by a bolt (not shown)
threaded into the end of the fitting. The gas fitting is on the low
pressure side of the pressure regulator 29 and connects to a
flexible plastic tube 31 which is passed through the side of the
canister and thence through a grommet 32 (FIG. 2) to the interior
of the hood. In this way gas from the regulator passes from the
canister into the hood for breathing by the user of the survival
support device.
The control mechanism 26 is further illustrated in perspective in
FIG. 4 and in a cross-sectional view in FIG. 5. As illustrated
therein, the control mechanism has a metal body 35 containing a
variety of apertures and passages within which various portions of
the control mechanism are positioned. The body and the associated
mechanisms are preferably capable of withstanding an internal
pressure of at least 5,000 psi to provide a substantial margin of
safety when the gas reservoir of coiled tubing is charged with a
breathable gas at 3,500 psi. Such strengths are readily attainable
since the entire control mechanism is small and the internal
passages and chambers are also of small diameter. Oxygen or an
oxygen rich mixture stored at 3,500 psi is sufficient for providing
breathable gas for at least 10 minutes.
A small-diameter metal tube 36 is welded into the control mechanism
body 35 at one end, and at the other end the tube has a
conventional gas fitting 37 for connection to a mating fitting (not
shown) at one end of the tubing 22 (FIG. 3) forming the principal
gas reservoir. The tube 36 thus provides fluid communication
between the control mechanism and the gas reservoir. The interior
of the tube 36 communicates with a transverse passage 38 within the
body 35. One end of the transverse passage 38 is closed by a sheet
aluminum diaphragm 39, discussed in greater detail hereinafter. The
other end of the passage 38 communicates with a bore 41 into which
a conventional pressure gauge 42 is threaded for indicating the
internal pressure in the bore 41, and hence within the gas
reservoir.
A passsage having a conical sealing surface 43 communicates with
the bore 41 and is sealed by a ball 44 mounted in one end of a plug
46. The plug 46 includes a pair of opposed fingers 47 for holding
the ball in place and substantially aligned with the axis of the
plug. At its opposite end the plug 46 includes a socket 48 for a
hexagonal wrench or the like so that the plug can be rotated in its
threads to bring the ball 44 in tight engagement with the conical
surface 43 to close the valve, or to withdraw the ball for opening
the valve. A pair of passages 49 extend through the plug off of the
axis thereof for passing gas through the plug from a threaded bore
51 in the body 35. Thus, in order to fill the gas reservoir, the
plug 46 is screwed out a short distance to raise the ball 44 off of
the conical surface 43. Pressurized gas admitted through the
threaded bore 51 passes through the passages 49 and into the
interior of the control mechanism body 35 so as to communicate
through the tube 36 into the gas reservoir. After the reservoir has
been charged to the desired pressure, the plug 46 is screwed down
again to seat the ball against the conical surface and thereby
close the valve. Although it is preferred to have the fill valve
mounted in the control mechanism body, a fill arrangement can be
provided at the end of the coil of tubing remote from the end
connected to the control mechanism. A check valve type of fill
valve can also be used, but the sealing reliability is not as high
as the positive valve illustrated.
After the fill valve has been closed, the survival support device
is ready for use and can sit on the shelf or be carried by a person
for long periods of time without recharging. The pressure gauge 42
provides an indication of the pressure within the reservoir to
confirm that a sufficient quantity of gas is stored for at least
ten minutes of use when the device is activated. If the gauge
indicates that the pressure has dropped due to slow leakage from
the system, it is only necessary to reopen the fill valve to bring
the pressure back up to the desired level.
Since the survival support device may sit on the shelf or be
inactive for a prolonged period of time and then need to be
activated rapidly and reliably on a moment's notice, a "one shot"
actuation mechanism is provided. The aluminum sheet diaphragm 39
sealing the passage 38 is typically installed as a partially drawn
shallow cup that is further deformed into the illustrated form of a
truncated cone by a retainer 52, thereby effecting a tight metal to
metal seal between the diaphragm and the opposed conical surfaces
on the retainer and the body. This tight seal persists for long
periods of time without deterioration.
An actuator body 53 is threaded into a bore in the control
mechanism body 35 coaxial with the passage 38. This actuator body
53 serves to press the retainer ring 52 tightly against the
aluminum diaphragm 39 to hold it in sealing engagement. The
actuator body 53 has a cylindrical bore 54 within which a plunger
56 is mounted. A conventional O-ring 57 seals the plunger 56 to the
cylindrical bore 54 to prevent gas leakage when the system is
actuated. During static conditions before the device is actuated,
there is no pressure across the O-ring 57 since the gas pressure is
retained by the diaphragm seal 39. The plunger 56 is biased towards
the diaphragm 39 by a compression spring 58. The plunger is
retained in a retracted position, as illustrated in FIG. 5 by a
pull pin 59, extending through a transverse hole 61 in the end of
the plunger. The side of the pull pin 59 bears against the end of
the actuator body 53 so that when the plunger is in its retracted
or cocked position, the spring 58 is under compression.
At the opposite end of the plunger 56 from the pull pin is a
perforating tip 62, also illustrated in the perspective view of
FIG. 6 and the end view of FIG. 7. The tip 62 has a diagonal flat
face 63 at about 45 degrees to the axis of the plunger. A pair of
flat faces 64 about 90.degree. apart and parallel to the axis of
the plunger intersect the flat face 63 so as to form a sharp point
at the tip of the plunger adjacent the diaphragm 39. The tip 62
also has a rounded portion 66 which permits it to enter the end
passage 38 upon actuation of the device. A gas relief slot 67 is
provided in the tip 62 intersecting the diagonal face 63.
In order to actuate the survival support device, the pull pin 59 is
withdrawn from the hole 61 in the plunger 56. A ring 65 (FIG. 3) is
connected on the end of the pull pin on the outside of the canister
so that it can be withdrawn quickly and easily in an emergency. The
compression spring 58 then quickly drives the plunger inwardly and
causes the tip 62 to perforate the aluminum sheet diaphragm 39. Gas
contained in the gas reservoir flows through the perforated
diaphragm by way of the slot 67 and into the bore 54 of the
actuator body 53. A pair of transverse passages 68 permit the
pressurized gas to flow from within the actuator body to a threaded
bore 69 into which the pressure regulator 29 is threaded.
The diaphragm and associated actuator mechanism for perforating it
thus keep the pressure regulator isolated from the high pressure
gas in the reservoir until the survival support device is actuated
and when the pull pin is pulled, the regulator is substantially
instantly connected to the reservoir so that gas quickly flows into
the hood.
The pressure regulator 29 has a post 71 threaded into the bore 69
in the control mechanism body 35. An axial passage 72 through most
of the length of the post and ending in a transverse passage 73
permits gas to flow from the bore 69 into a small chamber 74
defined by the sides of the post and a movable piston 76. The end
of the post 71 has a shallow conical depression that forms a blunt
knife edge 77 around the end of the post. A cap 75 threaded on the
post retains the piston 76 in position and compresses a compression
spring 78. A recessed region in the inside end of the cap and/or in
the end of the piston 76 forms a chamber 79 extending over
substantially the entire end area of the piston.
An outlet fitting 81 having a conical cap end 82 fits into the cap
75 and is held in place by the nut 27. The conical end 82 thus
tightly engages the inside of the cap to form a gas seal. A small
diameter orifice 83 separates the chamber 79 within the cap from
the balance of the outlet fitting 81 for limiting the flow of gas.
The fitting 28 (FIG. 3) that provides gas communication to the hood
is threaded onto the outlet fitting 81 when installed in the
survival support device.
When gas flows through the passages 72 and 73 through the post 71
from the bore 69 of the control device, it fills the chamber 74. It
can then flow past the knife edge 77 into the relatively larger
area chamber 79 opposite the face of the piston. The flow of gas
out of the chamber 79 is restricted by the small orifice 83 so that
there is a pressure buildup within the chamber 79 that acts on the
face of the piston 76. This increased pressure compresses the
spring 78, thereby pressing the inside surface of the piston
towards the knife edge 77 on the post. As the gap between the
piston and knife edge closes, the flow of gas is constricted so
that pressure within the chamber 79 can decrease as gas flows
through the orifice 83. A balance between the pressure in the
chamber 79 and compression of the spring 78 is quickly achieved so
that the pressure in the chamber 79 remains substantially constant
and, therefore, the flow rate of gas through the flow limiting
orifice 83 is also constant. The areas upon which the high pressure
gas within the chamber 74 can act on the piston are balanced so
that the magnitude of the high pressure within the regulator has
negligible effect on the pressure within the outlet chamber 79.
The volume of the outlet chamber 79 is less than 0.01 cubic inch
and the diameter of the orifice 83 is typically 0.01 inch. With
such dimensions the pressure in the chamber 79 is quite responsive
and equilibrium is rapid. The small volume coupled with the orifice
permits a single stage of pressure regulation to be used rather
than a double stage, thereby reducing cost, weight, and volume.
Thus, it is seen that the regulator 29 is a combined pressure
regulator and flow control so that substantially constant gas flow
is obtained through the outlet fitting 81 despite gross changes in
pressure within the gas reservoir. In a typical embodiment, the gas
in the reservoir is initially at about 3,500 psi, and this pressure
steadily drops towards ambient during the approximately ten minute
useful life of a charge of gas in the survival support device being
at about 250 psi after 10 minutes. Throughout this broad inlet
pressure range, a substantially constant flow of gas passes through
the outlet fitting 81 and hence into the hood 12 for breathing by
the user thereof. Tests have shown that the pressure at the outlet
of the regulator portion is readily maintained at 200 psi, .+-.20
psi, over the entire range from about 5,000 psi down to 250 psi on
the inlet side. Thus there is substantially constant gas flow into
the hood over a 20 to 1 range of storage reservoir pressures. If
the pressure drop across the orifice 83 had a 20 to 1 variation,
the gas flow would need to be excessively high initially in order
to be adequate near the end and the total usable time of the
survival support device would be significantly curtailed.
The sheet aluminum diaphragm 39 seals the gas in the reservoir
until such time as the pull pin is pulled, thereby releasing the
plunger, perforating the diaphragm, and actuating the survival
support device. The diaphragm also serves an additional function in
assuring safety of the survival support device in case of
over-pressurization. The thickness and strength of the aluminum
sheet forming the diaphragm 39 is well known so that the pressure
required to rupture the sheet can be determined. The thickness is,
therefore, selected so that the diaphragm will burst at a selected
pressure in excess of the pressure of gas in the reservoir and less
than the pressure required to damage other components of the system
such as, for example, the tubing forming the reservoir. With such
an arrangement, the survival support device cannot be dangerously
over-pressurized since such overpressurization would burst the
diaphragm 39, permitting the gas to flow through the pressure
regulator 29 to be safely exhausted through the hood at a nominal
rate. In the absence of overpressurization, the diaphragm remains
intact until actuation when the tip of the plunger pierces it.
FIGS. 8 through 10 illustrate another embodiment of survival
support device constructed according to principles of this
invention. In some respects, this embodiment is preferred to that
illustrated in FIGS. 1 to 3 since it may be lighter in weight for
the same total operating time, is somewhat more comfortable to
wear, and occupies a smaller total volume. These advantages come
about since the coiled tubing forming the gas storage reservoir is
bent in a quadrilateral pattern rather than a circular pattern so
that the interior space within the coiled tubing more closely
conforms to the external configuration of the control mechanism 26.
Thus, there is less unoccupied volume in the gas storage part of
the system. In addition, the surrounding metal canister is
dispensed with and the control mechanism is supported directly from
the coiled gas reservoir tubing.
FIG. 8 illustrates in back view a hood 86 substantially identical
to the hood 12 hereinabove described for fitting over a user's head
when the survival support device is activated. An elastic band 87
at the neck of the hood fits snugly around the user's neck for
inhibiting gas flow. Attached directly to the back of the hood is a
sheet plastic muff 88, open at its opposite ends and having a lower
flap 89 shown with one corner curled back in FIG. 8. The muff also
comprises an upper flap 91, a corner of which is also curled back
in FIG. 8. A embodiment of stainless steel tubing forming a gas
reservoir 92 is contained within the muff 88. The gas reservoir 92
is placed within the muff and the upper flap 91 connected to the
lower flap 89 by conventional snaps 93. The muff is made so that
the plastic is tightly stretched over the reservoir 92 when the
snaps are fastened, so that the gas reservoir is held in position
to fit against the nape of a user's neck when the hood is pulled
over his head. As in the ebodiment hereinabove described, a plastic
tube 94 conducts breathable gas from the gas reservoir through a
grommet 96 into the interior of the hood 86 when the survival
support device is activated.
Referring now to FIGS. 9 and 10, the gas reservoir 92 is seen in
end view and side cutaway, respectively. As best seen in the end
view of FIG. 9, the gas reservoir is in the form of a continuous
double coil of tubing with an inner coil 97 concentric with an
outer coil 98. Each of the coils 97 and 98 is somewhat squared off
so as to be bent in a quadrilateral figure with rounded corners as
compared with the circular coils of tubing employed in the
embodiment hereinabove described and illustrated in FIGS. 1 and 3.
Thus, in the first embodiment the gas reservoir is in the form of a
right circular cylinder, and in the embodiment illustrated in FIGS.
8 through 10, the gas reservoir is in the form of a cylinder having
a substantially quadrilateral cross section.
Mounted within the inner coil of tubing 97 forming the gas
reservoir is a control mechanism 126 substantially identical to the
control mechanism 26 hereinabove described and illustrated in FIGS.
4 to 7. The body 135 of the control mechanism is approximately
rectangular and closely fits within the inner coil of tubing 97 so
that there is a minimum of unoccupied volume within the coils
forming the gas reservoir. This more efficient utilization of the
volume reduces the total size of the gas supply subsystem of the
survival support device.
A bracket 99 having slightly curved ends 101 to conform to the
shape of the tubing forming the gas reservoir is connected to the
control mechanism 126 by a bolt 102. If desired, a shallow cup over
the end of the reservoir can be used and this may afford protection
for the gauge and keep the pull pin captive after the device is
actuated. The length of the control mechanism 126 is less than the
coiled length of the tubing forming the gas reservoir, and
therefore the opposite end of the control mechanism 126 is bolted
to a U-shaped bracket 103 illustrated in the cutaway view of FIG.
10. The U-shaped bracket 103 has wings 104 extending over the end
of the gas reservoir 92 so that when assembled, the coils of tubing
are clamped together and the control mechanism is firmly secured
thereto within the inner coil. A high pressure gas tube 136
connects the body of the control mechanism 126 to the gas reservoir
92 by a conventional fitting 137 in the same manner hereinabove
described. If the tube 136 is made sufficiently stiff, it may
provide support for one end of the control mechanism, permitting
deletion of one bracket.
At the end of the control mechanism approximately flush with the
end of the gas reservoir 92 is a pressure gauge 142 for monitoring
the state of readiness of the survival support device. A pull pin
159 attached to a ring 165 is employed in the same manner as
hereinabove described for actuating the survival support device.
Filling of the gas reservoir is accomplished at the opposite end of
the control mechanism, which is recessed from the end of the gas
reservoir. Thus, in both embodiments of survival support device
described and illustrated herein, a filling tool elongated enough
to fit down to the fill valve is employed so that it is not
necessary to remove the control assembly from the reservoir for
filling.
Such a special fill tool is illustrated in longitudinal cross
section in FIG. 11. The fill tool has an inner end fitting 110
having a threaded end 111 that is matable with the threaded bore 51
(FIG. 5) in the control mechanism. A suitable seal (not shown) may
be employed between the inner end fitting 110 and the body of the
control mechanism for preventing gas leakage when the fill tool is
used. Threaded into the opposite end of the inner fitting 110 is a
tube 112 of a sufficient length to provide gas communication
between the inner end fitting 110 when threaded into a fill valve,
and an external gas supply. Connection to the external gas supply
(not shown) is made by an outer end fitting 113 threaded on the
opposite end of the tube 112. Both the inner and outer end fittings
are also welded to the tubing 112 after assembly to assure a gas
seal and permanence of the connection. A transverse threaded bore
106 communicates with the interior of the outer end fitting 113 for
connection in a conventional manner with a high pressure gas
supply.
An axial passage 107 extends along the full length of the fill
tool. A shaft 108 in the passage 107 extends along a principal
portion of the length of the fill tool and has one end extending
through the tube 112 to butt against the interior of the inner end
fitting 110. A hexagonal socket 109 in the inner end of the shaft
108 mates with a hexagonal key 116 having sufficient length that an
end thereof can extend beyond the end of the inner end fitting 110.
A generally cylindrical sleeve 117 press fitted on the key 116
keeps the key captive within the inner end fitting. A flat side 118
on the sleeve 117 permits gas to flow along its length. A
compression spring 119 biases the sleeve 117 and the key 116
towards the end of the fill tool so that the end of the key
typically protrudes, as illustrated in FIG. 11. The socket 109 in
the end of the shaft is sufficiently deep that the key can be
depressed as required to permit assembly of the filling tool into
the fill valve.
At the opposite end of the shaft 108 an O-ring 121 provides a gas
seal to the outer end fitting 113. A shoulder on the shaft 108
bears against a bushing 122 which engages a conventional thrust
bearing 123. A retainer 124 threaded into the outer fitting 113
preloads the thrust bearing to a degree that permits the shaft to
be rotated during use. A hexagonal socket 125 is provided in the
outer end of the shaft 108.
In order to use the fill tool, the threaded portion 111 is
tightened into the bore 51 (FIG. 5) of the control mechanism. The
outer end fitting 113 on the fill tool is preferably hexagonal to
permit such tightening. When the fill tool is tightened in the
control mechanism, the hexagonal key 116 fits into the hexagonal
socket 48 (FIG. 5) in the fill valve. The key and the shaft 108 are
free to rotate as the fill valve stays fixed and the fill tool
rotates as it is tightened in place. The shaft 108 can then be
rotated by inserting a conventional hexagonal key (not shown) in
the hexagonal socket 125 at the outer end of the fill tool. This
motion is transmitted through the length of the fill tool so as to
open the fill valve in the control mechanism by baking the plug 46
out of its bore. High pressure gas may then be admitted through the
bore 106 in the fill tool to pass around the shaft 108 and past the
sleeve 117 into the body of the control mechanism where it is
transmitted to the gas reservoir as hereinabove described. After
the reservoir is charged to the desired pressure, the fill valve is
closed by rotating the shaft of the fill tool and the tool can then
be removed and the survival support device is ready for use.
Although but two embodiments of survival support device constructed
according to principles of this invention have been described and
illustrated herein, many modifications and variations will be
apparent to one skilled in the art. Thus, for example, three
concentric coils of tubing can be employed to form a gas reservoir
around a control mechanism to provide greater storage capability
and, hence, greater operating time or, on the other hand, the total
length of the gas reservoir can be decreased as the diameter is
increased without change in the operating time. Modifications and
variations in the arrangement within the control mechanism can also
be provided by one skilled in the art. Many other modifications and
variations will be apparent, and it is therefore to be understood
that within the scope of the appended claims the invention may be
practiced otherwise than as specifically described.
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