U.S. patent number 3,690,695 [Application Number 05/063,750] was granted by the patent office on 1972-09-12 for personnel restraint system for vehicular occupants.
Invention is credited to 91105, John Leslie Jones, Sr., 1070 Glen Oaks Blvd..
United States Patent |
3,690,695 |
|
September 12, 1972 |
PERSONNEL RESTRAINT SYSTEM FOR VEHICULAR OCCUPANTS
Abstract
The personnel restraint system has an accordion pleated impact
restraint bag, which is folded flat in a transverse U-bend and
disposed in a case, which can be fixed under the vehicle instrument
panel, adjacent to the front seat. In a quickly acting process an
adjacently disposed tank of liquid carbon dioxide charge, is
rapidly discharged through a ruptured tank sealing metal membrane
on activating an impact sensor and firing a squib. Concurrently
magnesium metal powder is blown into a metal combustion chamber
duct and rapidly oxidized. The heat of combustion is utilized to
vaporize the discharged liquid carbon dioxide to gas in the chamber
duct. The heated carbon dioxide gas is ducted into the folded
impact bag, rapidly expanding the bag into the vehicle compartment
volume in front of the personnel seats. A second impact sensor can
operate a second carbon dioxide tank which vents into the
atmosphere adjacent to the gasoline tank, acting to flood the tank
vicinity with carbon dioxide, to prevent or extinguish a gasoline
fire.
Inventors: |
John Leslie Jones, Sr., 1070 Glen
Oaks Blvd. (Pasadena, CA), 91105 (N/A) |
Family
ID: |
22051248 |
Appl.
No.: |
05/063,750 |
Filed: |
August 14, 1970 |
Current U.S.
Class: |
280/741; 102/531;
222/5; 200/61.45R |
Current CPC
Class: |
B60R
21/272 (20130101); H01H 35/14 (20130101) |
Current International
Class: |
B60R
21/26 (20060101); H01H 35/14 (20060101); B60r
021/06 () |
Field of
Search: |
;280/150AB ;23/281
;222/3,5 ;9/316 ;62/46-50 ;102/39 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kenneth H. Betts
Attorney, Agent or Firm: J. L. Jones, Sr.
Claims
I claim:
1. In a process for rapidly operating a personnel restraint system
suitable for protecting vehicular occupants, utilizing liquid
carbon dioxide sealed in a tank, said carbon dioxide vaporizing on
release from said tank and filling an impact restraint bag with
carbon dioxide gas, the process improvement comprising: a.
propelling and igniting a magnesium pyrotechnic composition by an
electrically ignited firing squib, said squib evolving gas at a
flame temperature adapted to igniting said magnesium composition;
b. combusting said magnesium composition with the oxygen of the air
resident in a combustion duct; and c. heating and flashing all said
released carbon dioxide to a gas, utilizing the turbulent heat
transfer from the reaction products of the magnesium combustion
process, said reaction products adapted to providing the required
heat of vaporization for the liquid carbon dioxide.
2. In a process for rapidly operating a personnel restraint system
suitable for protecting vehicular occupants, utilizing liquid
carbon dioxide sealed in a tank by a thin metal diaphragm, said
carbon dioxide vaporizing on puncturing said diaphragm and filling
an impact restraint bag with carbon dioxide gas, the improved
process comprising: a. electrically igniting a squib, said squib
evolving a required volume of high pressure gas at a flame
temperature adapted to ignite a magnesium composition in air; b.
propelling a cutter knife to puncture said diaphragm, said knife
propelled by said high pressure gas evolved by said squib; c.
concurrently with propelling said cutter knife, igniting and
propelling said magnesium composition into a metal combustion duct,
said magnesium composition rapidly combusting in and with the
oxygen of the air resident in said duct and evolving heat; and d.
heating and rapidly vaporizing said released carbon dioxide to a
gas, adaptively utilizing the evolving heat of combustion
turbulently transferred from the products of combustion to flash
all said carbon dioxide.
3. In a carbon dioxide inflating gas, automated personnel restraint
system for personnel carrying vehicles, having a liquid carbon
dioxide gas supply disposed in a tank sealed by a thin rupturable
metal diaphragm, the improvement comprising: a. an electrically
ignitible firing squib, adapted on igniting to evolving a required
volume of high pressure gas at a flame temperature adapted to
igniting a magnesium composition, and to rapidly propelling a
cutter knife and rupturing said diaphragm, said squib being
electrically insulatively disposed in a squib enclosure in said
tank neck adapted to withstand said gas pressure; b. at least one
case cooperatively radially integrally connected to said tank neck
and opening into said squib enclosure on propelling said knife to a
predetermined tank neck stop; c. a predetermined weight of
magnesium pyrotechnic composition cooperatively disposed in said at
least one case, said composition secured in said case by a pair of
very thin foil membranes, said predetermined weight of said
composition evolving a predetermined heat of combustion with the
oxygen of the air; d. a metal tubular duct cooperatively adaptively
securely containing said carbon dioxide tank in a fixed position at
one end of said duct, the duct volume containing sufficient oxygen
in the contained air to combust said magnesium composition, the
weight of said metal duct providing adequately safe strength and
heat transfer characteristics for the magnesium combustion
reaction; e. a cover means for a first end of said duct disposed
adjacent said carbon dioxide tank; f. insulated electrically
conductive wire means connecting said electric squib to an impact
sensor means disposed exteriorly to said duct; and g. a tubular
coupling means, conductively tightly connecting the gas exit of the
second duct end to a flexible membrane gas inlet tube of an impact
restraint bag.
4. In the automated personnel restraint system improvement of claim
3, the further improvement wherein at least one mixing orfice is
coaxially disposed in said duct adjacent said metal cases
containing magnesium composition, said at least one orfice having a
coaxially disposed mixing aperture.
5. In the automated personnel restraint system improvement of claim
3, the further improvement wherein a metal heat exchanger is
coaxially disposed in said duct adjacent said second duct end.
6. In a carbon dioxide inflating gas, automated personnel restraint
system for personnel carrying vehicles, having a liquid carbon
dioxide gas supply disposed in a tank sealed by a thin rupturable
metal diaphragm, the improvement comprising: a. a cutter knife
coaxially slidably disposed in the tank neck exteriorly disposed to
rupturing said metal diaphragm, said knife having cutting edges
adjacently disposed to said diaphragm and a piston face oppositely
disposed to said cutting edges, said knife having positioning
shoulders thereon, adapted to stop said knife in a cooperatively
predetermined position on a tank neck stop on propelling said
knife; b. an electrically ignitible firing squib, adapted on
igniting to evolving a required volume of high pressure gas at a
flame temperature adapted to igniting a magnesium composition, and
to rapidly propelling said cutter knife and rupturing said
diaphragm, said squib being electrically insulatively and loosely
disposed in a squib enclosure in said tank neck adapted to
withstand said gas pressure; c. at least one case cooperatively
radially integrally connected to said tank neck and opening into
said squib enclosure on propelling said knife to said predetermined
tank neck stops; d. a predetermined weight of magnesium pyrotechnic
composition cooperatively disposed in said at least one case, said
composition secured in said case by a pair of very thin foil
membranes, said predetermined weight of said composition evolving a
predetermined heat of combustion with the oxygen of the air; e. a
metal tubular duct cooperatively adaptively securely containing
said carbon dioxide tank in a fixed position at a first end of said
duct, the duct volume containing sufficient oxygen in the contained
air to combust said magnesium composition, the weight of said metal
duct providing adequately safe strength and heat transfer
characteristics for the magnesium combustion reaction; f. a cover
means for said first end of said duct disposed adjacent said carbon
dioxide tank; g. insulated electrically conductive wire means
connecting said electric squib to an impact sensor means disposed
exteriorly to said duct; and h. a tubular coupling means,
conductively tightly connecting the gas exit of the second duct end
to a flexible membrane gas inlet tube of an impact restraint
bag.
7. In the automated personnel restraint system improvement of claim
6, the further improvement wherein at least one mixing orfice is
coaxially disposed in said duct adjacent said metal cases
containing magnesium composition, said at least one orfice having a
coaxially disposed mixing aperture.
8. In the automated personnel restraint system improvement of claim
6, the further improvement wherein a metal heat exchanger is
coaxially disposed in said duct adjacent said second duct end.
9. In the automated personnel restraint system improvement of claim
6, the further improvement wherein a. a multiple accordion pleated
folds, flexible membrane, non-combustible, impact restraint bag,
having a bag height, width and length of suitable dimensions, is
folded flat in the plane of said multiple folds; and b. a flexible
membrane, non-combustible, distending gas inlet tube is permanently
cooperatively affixed to a bag face aperture, at a first inlet tube
terminus, and is secured to aid tubular coupling means at a second
inlet tube terminus.
10. In the automated personnel restraint system improvement of
claim 6, the further improvement wherein, the multiple accordion
pleated folded flat impact restraint bag has a transverse axial
U-fold.
11. In the automated personnel restraint system improvement of
claim 6, the further improvement wherein, a long, flat protective
case encloses said impact restraint bag and said gas inlet tube,
said case having a shallow top case cover and a shallow bottom case
cover, said top and bottom case covers having confronting case
front lips, and having an integral frangible plastic hinge
cooperatively securing the confronting case rear lips together,
said integral frangible plastic hinge closely securing said top and
bottom case cover prior to the breaking of said frangible hinge on
expansion of said gas inlet tube and said restraint bag.
12. In the automated personnel restraint system improvement of
claim 11 the further improvement wherein a flexible hinge also
cooperatively secures said confronting case rear lips together.
13. In the automated personnel restraint system improvement of
claim 6, the further improvement wherein said tank neck adaptively
points to said second duct terminus.
14. In a carbon dioxide inflating gas, automated personnel
restraint system for personnel carrying vehicles, having a carbon
dioxide liquid supply disposed in a sealed tank, the combination
comprising: a tubular duct; a cover means sealing a first duct
terminus, adjacent to a first duct end section; a sealed tank
containing liquid carbon dioxide, said tank secured in said first
duct end section; a tank venting means, providing rapid release of
said liquid carbon dioxide from said tank on signal; a combustible
metal composition disposed adjacent said tank venting means, said
composition providing heat energy on burning in the air resident in
said duct; an ignition means, on signal concurrently actuating said
tank ventilation and metal combustion ignition; whereby the heat of
combustion of said metal composition provides the required energy
for rapidly vaporizing said liquid carbon dioxide to gas, in said
tubular duct.
15. In the automated personnel restraint system improvement of
claim 14, the further improvement wherein the metal composition is
a magnesium pyrotechnic composition.
Description
There is a serious current need for a personnel restraint system
for motor vehicles and the like, which can cushion and restrain the
moving occupant of a passenger car, truck and an airplane when the
vehicle suddenly impacts in an accident. Typically the personnel
restraint system should guarantee protection against a head-on
collision with a fixed barrier at 30 mph, without requiring
voluntary participation by the vehicle's occupants, such as
fastening seat belts, shoulder harnesses, or the like. The
personnel should also be protected in lateral collisions at speeds
up to 15 mph and from two complete vehicle rollovers at speeds up
to 60 mph. The system should sense the varying crash situations and
the impact bag should be triggered and deployed without harming the
passengers, in less than 50 millisec.
One current personnel restraint system utilizes a 3,500 psi air
tank source which empties into a woven nylon impact bag, once a
thin metal tank diaphragm is punctured. An electronic
omnidirectional sensor has redundant impact sensors. In another
personnel restraint system compressed nitrogen gas is vented into
an impact bag when the electrically fired dentonator opens the high
pressure, tubular gas reservoir assembly. The high velocity gas
flows through a controlled opening and is directed into the air bag
through a diffuser system. A uni-directional sensor is employed in
this personnel restraint system.
In still another system, a solid-state storage supply is proposed
for the inflating gas. This inflation system requires a solid
propellant charge which on combustion will not generate toxic gases
and the propellant must burn at as low a temperature as possible,
to decrease fire hazards. A suggested solid propellant generating
gas suitable for the inflation of the impact bag has a solid
coolant, ammonium oxalate, added to eliminate toxic gases such as
hydrogen cyanide, hydrogen sulphide, carbon monoxide, and the
like.
This invention eliminates the excessively high pressure gas storage
requirement of the nitrogen tank, and the potential formation of
toxic gases in the occupant compartment of the vehicle. It
decreases the noise level of the operation of the personnel
restraint system and increases the reliability of the automatic
system activation by using an initiating squib or fuse. By rapidly
flashing the liquid carbon dioxide with the heat of combustion of
an ignitible magnesium composition, low cost and low storage
pressure carbon dioxide is used.
SUMMARY
The personnel restraint system is activated by one or more spring
loaded impact sensors separately, permanently disposed in selected
locations in a vehicle. On impact, one or more sensors electrically
conduct at the sensor locations, firing a hot gas and flame
generating squib. The hot gas operates a device which opens the
metal diaphragm securing liquid carbon dioxide under pressure in a
cylinder, and also ignites one or more magnesium power charges
exteriorly disposed adjacent the cylinder exit orfice. The ignited
magnesium is blown down the metal combustion chamber, which also
confines the cylinder and the required air for metal powder
ignition. The finely divided, hot reaction product, magnesium
oxide, together with the heated residual air, and the radiating
metal combustion chamber, rapidly and effectively exchange heat to
raise the temperature of the liquid carbon dioxide being ejected
from the tank, quickly flashing the carbon dioxide to a warm gas.
The warm gas is quickly directed into one end of a flexible
non-combustible membrane tube, coaxially secured to the end of
metal heat exchanger duct. The membrane tube is permanently secured
at its second tube end to a flat folded, accordion pleated,
transverse axially U-folded, impact distortable, flexible membrane,
restraint bag. Prior to filling the bag with warm gas, the flat,
accordion pleated, U-folded bag is disposed in a protective, long,
flat plastic case. The case is disposed under the lower forward
edge of the typical car vehicle instrument panel, confronting the
front seat. The long, flat, U-folded bag is protected by a pair of
frangible hinged plastic covers of the case. A second integral
hinge secures the cover when gas fills the bag, projecting the bag
into the car volume adjacent the instrument panel and steering
wheel, as the folded bag pleats are filled with gas to the required
pressure. The same impact sensor or a second impact sensor can
operate to open a second carbon dioxide tank disposed adjacent the
gasoline tank, acting to flood the tank vicinity with carbon
dioxide to prevent or extinguish a gasoline fire.
The chain of chemical and physical reaction times required to
develop the restraint system to an operational safety condition are
minimal. Typically, 1.14 lb. of liquid carbon dioxide at 928 psia
and 77.degree. F., flashes to occupy 10.1 cu. ft. at 77.degree. F.
and 1 atm. The liquid carbon dioxide can be rapidly vaporized by
burning 2.47 gram of magnesium in 2.30 liters of oxygen in the air
in the duct, using gas mixing orfice devices and a heat exchanger
in the metal combustion chamber duct.
Included in the objects of this invention are:
First, to provide an integrated, rapidly acting, automated
personnel restraint system for a vehicle carrying occupants.
Second, to provide a simple, low cost, reliable, rapidly acting,
automatic carbon dioxide gas inflation means for a personnel
restraint system in a personnel carrying vehicle.
Third, to provide a modular, secure, reliable, rapidly acting
carbon dioxide gas inflation means for a personnel restraint system
disposed in a motor vehicle.
Fourth, to provide a low cost, reliable, rapidly acting, heat
exchange means for vaporizing liquid carbon dioxide in a gas
inflation means of a personnel restraint system for passenger
carrying vehicles.
Fifth, to provide a rapidly oxidizable, exothermic, heat exchange
reactive means for rapidly flashing liquid carbon dioxide in a
personnel restraint system disposed in a personnel carrying
vehicle.
Sixth, to provide a rapidly acting, igniting and gas pressurizing
means for a carbon dioxide gas inflating, personnel restraint
system for a personnel carrying vehicle.
Seventh, to provide an accordion pleated, transversely axially
U-folded, impact distortable, flexible membrane, impact restraint
bag and a frangible protective case for a personnel restraint
system for personnel carrying vehicles.
Eighth, to provide a rapidly acting, exothermic, heat exchange
reactive process for rapidly vaporizing liquid carbon dioxide in a
personnel restraint system disposed in a passenger carrying
vehicle.
Ninth, to provide a rapidly acting, igniting and gas pressurizing
process for a carbon dioxide powered personnel restraint system for
a personnel carrying vehicle.
Further objects and advantages of this invention will become
apparent in the following description, to be read in conjunction
with the accompanying drawings.
FIG. 1 is a flow sheet illustrating sequential steps in the
operation of the personnel restraint system.
FIG. 2 is a partial sectional planar view of important components
of the personnel restraint system.
FIG. 3 is a sectional view through 3--3 of FIG. 2.
FIG. 4 is a sectional view through 4--4 of FIG. 2.
FIG. 5 is a sectional view through 5--5 of FIG. 2.
FIG. 6 is a perspective view of the personnel restraint system
confrontingly disposed to the front seat and under the instrument
panel adjacent to the firewall of a motor vehicle.
FIG. 7 is a partial sectional view of the carbon dioxide and the
system firing mechanism in 6, along the line 7--7 of FIG. 2.
FIG. 8 is a sectional view of the firing system mechanism of FIG. 7
disposed in the combustion chamber duct of FIG. 2, after ignition
of the magnesium reactant, illustrating the carbon dioxide venting
mechanism operation, as well as the ignition of the magnesium.
FIG. 9 is a perspective view of the typical structure of the carbon
dioxide tank metal diaphragm knife cutter.
FIG. 10 is a perspective elevational view of the accordion pleated
personnel impact bag, partially distended as it is being ejected
from the bag carrying case, on filling with carbon dioxide gas.
FIG. 11 is a perspective elevational view of the impact sensor
mechanism with the dirt protective cover removed.
FIG. 12 is a sectional view of the impact sensor of FIG. 11,
illustrating further details of the construction of the sensor,
enclosed in a permanently sealed dirt protective cover.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates in a flow sheet important steps required for the
operation of the personnel restraint system 1. Illustrated first in
box II, an impact sensor is activated, signalling that a personnel
carrying vehicle is involved in an accident resulting in the rapid
deceleration or acceleration of the vehicle or of the vehicle
component to which the impact sensor has been permanently secured.
The impact sensor, which is an electrical switch, closes the
electrical circuit igniting a squib, which in turn vents a carbon
dioxide tank as is indicated in the next step of box III. At a very
short millisecond interval thereafter, a magnesium pyrotechnic
composition is exothermically burned in a combustion chamber as
illustrated in box IV. At a still later short millisecond interval,
the liquid carbon dioxide is ejected from the carbon dioxide tank
under pressure and flashes to a gas in the combustion chamber. The
heat of vaporization of the liquid carbon dioxide is supplied by
the exothermic heat of combustion of the magnesium as illustrated
in box V. The warm carbon dioxide gas fills and ejects the impact
restraint bag, as shown in box VI. The gas filled impact restraint
bag then restrains and cushions any personnel thrown against the
bag during an accident or the like.
Referring to FIG. 2 in detail, the personnel restraint system 1 is
shown in planar, partial sectional view, having an L-shaped metal
duct 2. The duct 2 typically extends from the A to B as shown by
the arrow 3. At the cylindrical duct end A, a metal duct cover 4 is
secured to the duct 2. A tank 5 containing liquid carbon dioxide is
disposed inside the duct 2, adjacent to the duct cover 4 and is
permanently secured in place in the duct 2 by known standard means.
A system firing mechanism 6 is shown secured to the tank 5. A pair
of ignition wires 7 and 8 extend from the firing mechanism 6 around
the side of the tank and through the respective electrical
insulator connectors 9 and 10 in the metal duct cover 4. The
igniter wires 7 and 8 are then connected through an impact sensor
switch 11 shown schematically as an equivalent electrical switch.
The car battery 12 or an equivalent power source supplies power to
actuate the system firing mechanism 6 when the impact sensor 11 is
activated, as in an accident. A pair of combustion flame holders 13
and 14 also serve as mixing orfices for the combustion process
which will be discussed later. The combustion flame holders 13 and
14 are secured to the interior wall of duct 2 and have a respective
pair of mixing apertures 15 and 16. The duct elbow 17 continuously
connects to and terminates at the heat exchanger 18. A flexible
duct coupling means 19 is secured on the metal duct 2 by the
retaining ring 30 and connected to the carrying case 20, which
holds the impact restraint bag, not shown. The top half 25 of the
carrying case 20 is shown in planar view, having a transverse axis
26 for the restraint bag which is enclosed in the case 20. A
flexible membrane tube protective channel 21 of the case 20 is
indicated in dotted lines, as being disposed on the under side of
the case 20, connected to the flexible duct coupling 19.
In FIG. 3 the metal circular duct cross section 2 is shown, having
a combustion flame holder 13 coaxially disposed therein, with the
mixing aperture 15 also coaxially disposed therein. The duct 2 has
a typical diameter D. The function of the flame holder 13 is to
hold the ignition flame of the pyrotechnic composition, as well as
to produce mixing of the combustion products with the liquid carbon
dioxide as it is ejected from the tank 5, as will be later
described.
FIG. 4 also shows the circular duct 2 in cross sectional view with
a diameter D and having a heat exchanger 18 filling the cross
section for the length 27 along the duct 2, as shown in FIG. 2. The
heat exchanger 18 typically fits closely into the duct diameter D
and can be aluminum or copper wire screen of a suitable mesh size.
Exchanger 18 also can be an extruded copper, aluminum honeycomb
cross sectional or tubular structure, or other highly conductive
metal composition, which can rapidly absorb heat and transfer heat
to high velocity gases and liquids moving through the heat
exchanger 18. The heat exchanger 18 can also be an expanded
honeycomb type structure of sheet aluminum or the like, commonly
used as a light weight compression resistant member in aerodynamic
surfaces such as airplane wings, or the like. The light weight
aluminum honeycomb can be typically made by welding together a
multiplicity of very thin aluminum sheets in linear patterns, and
expanding the multiple sheet structure into an expanded honeycomb.
Other metal compositions of high heat conductivity can likewise be
used. The metal duct 2 and the heat exchanger 18 can also typically
be mild carbon steel. In terms of the optimization of heat transfer
rate vs the cost of the duct and its contained metal component raw
material weight, if a sufficiently rapid heat transfer can be
effected with steel, it can well be the most economical material
and construction.
In the cross sectional view through 5--5 of FIG. 2 as shown in FIG.
5, the plastic case 20 is shown to have a top case cover 25 and a
bottom case cover 22 secured together by a frangible hinge
structure 24. The case 20 has the frangible hinge 24, and a
transversely linear front line lip 28 formed by the contact of the
top case 25 with the bottom case 22. The permanent integral hinge
29 secures top case 25 and bottom case 22 together. The impact
restraint bag 23 is shown disposed inside the case 20, folded in a
transverse U-bend along the transverse axis 26 of the case 20. The
impact restraint bag 23 is shown to have accordion pleated multiple
folds in the bag as will be later disclosed in detail.
The frangible plastic hinge 24 should be secured to the case 20
after the impact restraint bag 23 is folded and disposed in the
case 20. Suitably, the bag 23 is disposed in the bottom 22 of the
case, then the top 25 of the case is placed in position at the
front line lip 28 and the integral frangible plastic hinge 24
bonded in place on the case 20 securing the case components
together. The frangible hinge 24, which can be sealed completely
along the length of the transverse axis 26 of the case can be a
molded structure having a notch disposed therein which renders the
hinge frangible at the notch cleavage. A plastic hinge composition
having a particularly high notch impact sensitivity, such as
polystyrene, or the like, is particularly suitable for the hinge
structure. Other plastic compositions having suitable notch impact
sensitivity may be utilized.
FIG. 6 illustrates the general configurational positioning of the
personnel restraint system 1 disposed in a motor vehicle. In the
illustration, the metal duct 2 enclosing the other typical
components of FIG. 2 is shown disposed underneath the instrument
panel 60 of the motor vehicle, with the duct 2 adjacent the
firewall 61 of the car. The front seat 62 of the motor vehicle
confronts the instrument panel 60 of the car in the usual
configuration. The carrying case 20 for the impact restraint bag
shown disposed underneath the instrument panel, with the case front
line lip 28 generally disposed parallel to the instrument panel and
adjacent to the panel 60. The top 25 of the carrying case 20 is
secured to the instrument panel by suitable well known means. The
protective channel 21 for the flexible membrane tube in the case 20
is shown disposed on the underside of the bottom case 22.
Operationally, the carrying case 20 is shown disposed as close to
the seat 62 as is comfortable and safe, in order to provide a
minimum transit time for the impact restraint bag 23 disposed
therein, when the personnel restraint system 1 is activated. The
flexible coupling 19 is shown, providing a flexible means for
permanently coupling the rigidly positioned carrying case and the
other rigidly positioned components of the personnel restraint
system 1, enclosed in the metal duct 2.
In FIG. 2 the duct 2 is shown disposed in a planar geometrical
position, and it is likewise shown in the same planar position in
the perspective view of FIG. 6. However, the duct 2 can be rotated
90.degree. to place the tank component 5, or the like, in a
vertical position, either with the duct cap 4, or the like, down
near the floor board of the car, or it may be placed vertically
uppermost with the system firing mechanism 6 disposed directly
below the raised tank 5, or the like. When the tank 5 is placed
vertically above the system firing mechanism 6, liquid carbon
dioxide will be ejected from tank 5 when the diaphragm 72 is
ruptured. In the other placement positions of the tank 5, more or
or less liquid carbon dioxide will be directly ejected from the
tank, depending on the angular position of the tank.
The details of the construction of the system firing mechanism 6
which are secured on the carbon dioxide tank 5 are shown in FIG. 7.
The internally threaded tank neck 70 of the carbon dioxide tank 5
is shown to have an internal collar 71 threaded into the neck 70. A
thin metal sealing diaphragm 72 seals the tank neck 70, securing
the internal tank volume 73 which contains liquid carbon dioxide. A
threaded sealing collar 74 compressively seals the metal diaphragm
72 against the internal collar 71. Thus a tank aperture 94 is
provided through which the liquid carbon dioxide can be eventually
ejected. Typically, a four edge cutter knife 75 is disposed in the
tank neck 70 adjacent to the metal diaphragm 72. A knife guide and
spacer 77 is typically secured in the tank neck 70, positioning the
cutter knife 75. A knife piston disc face 76 is integrally secured
to the cutter knife 75 and slidably closes and fills the
cylindrical diameter of the knife guide and spacer 77. A firing
squib 78 is disposed in the squib enclosure 82. The squib sealing
plug 79 seals the firing squib 78 in position. The plug 79 is
typically threaded or secured immediately abutting the knife guide
and spacer 77, providing a loose enclosure for the firing squib 78
and preventing the squib 78 from being prematurely crushed or
impacted into firing. The squib ignition wires 7 and 8 are
conducted from the firing squib 78 through the pair of insulator
connectors 80 and 81 to the remainder of the firing circuit. A pair
of metal elbow cases 83 and 84 are shown oppositely disposed in the
neck 70 of the tank 5. Additional metal elbow cases may also be
provided around the same radial plane of case 83 and 84. The metal
elbow cases 83 and 84 and the like are filled with the required
amount of magnesium pyrotechnic compositions 85, 86 and the like.
The magnesium pyrotechnic composition can be simple magnesium
powder, as is used in photography and the like. The metal elbow
cases 83, 84 and the like are sized to contain the required amount
of magnesium composition. Each elbow case, typically 83, has a pair
of very thin metal foil sealing membrances 87 and 88 which are
secured to the ends of the case and which secure the magnesium
composition in the case until the system becomes operational. A
similar pair of very thin metal sealing membranes 89 and 90 seal
the elbow case 84, or the like, containing the required magnesium
composition in it. The pair of apertures 91 and 92 each separately
connect the cases 83 and 84 respectively to the knife cavity 93 in
which the knife cutter 75 is disposed. The detailed structure of
the firing mechanism 6 which is illustrated in FIG. 7 is that which
exists in the configuration of the personnel restraint system 1 in
FIG. 2, prior to the initial operation of the system 1. It is
desirable that all of the components of the system 1 which lie
between the lines A and B should be metallic, providing that the
system can be well grounded except where electrical insulators are
required.
Referring to FIG. 8 in detail, the system firing mechanism 6 is
shown disposed in the partial sectional view within the metal duct
2. The details of the firing mechanism 6 are shown in operative
relationship after the firing squib 78 has been fired, converting
it to the ruptured squib 78'. The fired squib 78' still occupies
its essentially constant position within the squib enclosure 82,
but the knife cutter 75 is now shown driven through the thin metal
membrane 72 which previously sealed the interior of the tank 73.
The ruptured diaphragm 72' is shown bent in leaves at the side of
the tank aperture 94. The fired squib 78' has evolved both high
pressure gas and flame resulting from igniting the composition in
the squib. The high pressure gas has pressed against the knife
cutter piston face 76, moving the piston to cut the ruptured
diaphragm 72'. The high pressure gas and the flame from the squib
78' have blown the very thin foil metal membranes 87, 88, 89 and 90
of the cases 83 and 84 respectively, blowing out the magnesium
pyrotechnic composition contained in the cases 83 and 84. The
magnesium pyrotechnic compositions are ignited by the flame of
squib 78', and the magnesium composition burns in the oxygen of the
air resident in duct 2. For the purpose of insuring complete
combustion of the magnesium composition, the sizing of the duct
diameter D is that which provides sufficient oxygen in the resident
air in the duct to burn all of the magnesium composition. The
magnesium powder composition is blown in the direction of the
arrows 96 and 97 by the high pressure gas from the squib 78'. The
arrows 98 and 99 indicate the average direction of flow of the
reactants and combustion products in the chamber. For the purpose
of clarity, the sections 30 and 17 of FIG. 2 are designated as the
combustion chamber for the combustion of the magnesium. The
combustion flame holders 13 and 14 have been suitably disposed to
aid in the mixing of the reactants, as well as to provide flame
holders for assistance in the completion of the combustion. The
combustion process may also be completed in the absence of the
flame holders 13 and 14, but the flame holders can reduce the
required length and volume of the sections 30 and 17. The
combustion process can take place not only in the sections 30 and
17, but also in the heat exchanger 18.
Typically, the magnesium burns in the well known reaction,
2 Mg + 0.sub.2 .fwdarw. 2 Mg 0 .DELTA.H.sub.1 = -143.8
kcal/mole
In addition, magnesium ignited in air can also react with carbon
dioxide as illustrated in the equation (2) below,
2 Mg + CO.sub.2 .fwdarw. 2 Mg 0 + C .DELTA.H.sub.2 =- 96.8
kcal/mole (2) The fact that magnesium will react with carbon
dioxide is important for the rapid vaporization of the liquid
carbon dioxide as it is ejected under pressure from the tank 5, or
the like. Under the conditions of the operation of the personnel
restraint system 1, the carbon dioxide will not smother the
oxidation of the magnesium which precedes it, for reaction (2) is
also exothermic and will proceed with evolution of heat. Although
the heat of reaction of equation (2) is smaller than (1), the
reaction is sufficiently exothermic to provide energy for the
vaporization process. Allowance can be made for reaction (2) by
adding additional magnesium pyrotechnic composition, to the system
firing mechanism 6.
Typically, 1.14 pounds of liquid carbon dioxide (P vapor = 928 psia
at 77.degree. F.) flashes to occupy 10.1 cu. ft. at 77.degree. F.
and 1 atmosphere. The heat required to rapidly vaporize the liquid
carbon dioxide can be quickly obtained by burning 2.47 grams of
magnesium powder in 1.22 liters of oxygen in the air in the duct.
In order to prevent undue temperature rises within the duct and to
promote the efficiency of heat transfer in the vaporization
process, a heat exchanger can be desirable. The combustion of the
magnesium powder composition can be accelerated by utilizing finely
divided magnesium powder and by providing mixing orfices to promote
turbulence during the combustion process. The heat of vaporization
of the liquid carbon dioxide at varying ambient tank temperatures
can be compensated for by adding more than the theoretical amount
of required magnesium. Additional magnesium over the theoretical
will also compensate for combustion efficiency and heat transfer
efficiency.
FIG. 9 is an elevational perspective view of the knife cutter 75
showing the four thin knife edges of the cutter. The cutter is
shown to have the four knife shoulders 100 which can bear on the
collar 74, as at the area of contact 95 between the cutter 75 and
the collar 74 in FIG. 8. The cutter piston face 76 is shown to be
circular, dimensioned to snugly fit into the cavity 82 without
seizing or galling. Obviously other numbers of knife edges can be
provided for the cutter 75 or the like. The shoulders 100, or the
like, are provided as stops to position the cutter 75 after
actuation by the squib 78', so that the cutter apertures 101, as
outlined by the multiple blade edges, can allow passage of the
carbon dioxide from within the tank volume 73.
Referring to FIG. 10 in detail, after the combustion process takes
place in the chamber 30, 17, and 18, the flashed carbon dioxide gas
flows through the flexible coupling 19 into the impact restraint
bag 23. The flexible membrane tube 110 which previously has been
loosely lying in the protective channel 21 of the case 20 is now
filled with carbon dioxide gas under pressure. The tube 110 now
distends to its full length and snaps open the case 20, by breaking
the frangible hinge 24. The distending tube 110 now ejects the
accordion pleated impact restraint bag 23 which has been folded in
a U-bend along the transverse line 26 of the case 20. The ejected
impact bag 23 is forced out of the case by the pressure of the
carbon dioxide gas filling bag 23. The accordion pleated folds
typically 111 fill first at the face 112 of the bag adjacent to the
duct 110. The accordion pleated folds 113 furtherest from the bag
face 112 tend to be filled last as is illustrated. Depending upon
the precise weight filling of the tank 5 with the required amount
of liquid carbon dioxide, the bag 23 is fully distended with carbon
dioxide under a slight pressure within milliseconds after
activation of the switch 11, as in FIG. 2. By providing the
required amount of magnesium pyrotechnic composition, the liquid
carbon dioxide can be vaporized to carbon dioxide at a nominal
ambient room temperature of 70.degree.-90.degree. F. at a low
pressure of 1-2 lbs. or the like. The accordion pleated impact
restraint bag 23 has a length 114 when fully distended, which can
be sufficient to act as a restraint bag for 1, 2 or 3 personnel
occupying a motor vehicle seat, as required. The height 115 of the
fully distended restraint bag 23 is that which is necessary to
provide the impact restraint protection required for the personnel
in the vehicle, and can be typically 12 to 24 inches or the like.
For clarification, the transverse axis 116 of the bag 23 is shown,
about which the bag is folded into a U-bend when disposed in the
container 20.
The accordion pleated impact restraint bag 23 or the like can be
typically formed of a non-combustible thin flexible membrane
plastic material such as a polyvinyl chloride plasticized with a
non-combustible plasticizer, or it can be formed of a non-woven
fabric with a thermoplastic binder. It is possible to form the
non-flammable plasticized polyvinyl chloride bag in a standard blow
molding operation, utilizing well known commercial techniques.
Likewise a non-woven, non-flammable thermoplastic fiber composition
such as Dynel can be used to form a non-porous bag, which may be
fabricated in a pattern cutting and bonding operation.
Referring to FIG. 11 in detail, the unidirectional reactive impact
sensor components 120 are shown disposed on a structural component
121 of the personnel vehicle. The helical coil spring 122 is shown
disposed snugly and loosely slidably coaxially fitted around the
low friction coefficient electrical insulator post 123, having a
rounded terminal 124. The post 123 can typically be
polytetrafluoroethylene (Teflon) or other polyfluoropolymers, or
the like, having very low coefficients of friction, and sufficient
hardness to eliminate cold flow and distortion under the conditions
of use in this sensor. A rigid metal electrically conductive rod
end 125 is coterminus with the apex of the rounded post end 124
extending coaxially through the post 123 into the electrically
insulating base 126. The spring terminus 127 has an electrically
conducting metal weight 128 permanently secured to the spring, and
the weight 128 is disposed directly over the electrically
conducting rod end 125. The mass M of the metal weight 128, the gap
G between the weight 128 and the rod end 125, and the length L of
the electrically insulated post 123, together with the pitch
distance P between the turns of the helical coil spring 122 are
configured in terms of the physical constant k of the spring 122 to
provide electrical contact between the mass 128 and the rod end 125
at the required deceleration value to unidirectionally activate the
sensor components 120. An annular ring groove 129 is shown
coaxially disposed around the post 123, which is suitable for
securing a protective dust and water tight cover over the active
components 120. The sensor behaves as a seismic pendulum, having a
period, T = 2 .pi..sqroot.M/kg.
FIG. 12 illustrates in sectional detail the components of the
complete unidirectional impact sensor switch 130. All of the active
switch components of FIG. 11 are illustrated and the axially
disposed electrical conducting metal rod 131 is shown coaxially
disposed within the electrical insulator post 123, the rod 131
terminating at the electrical contact end 125. A water resistant
and dust proof cover 132 is coaxially disposed around the active
components 120 of the impact sensor 130. The lip 133 of the cover
132 is shown disposed in the coaxial groove 129. A threaded
container ring 134 is shown threaded into the groove 129 locking
the cover 132 into a permanent dust and water tight protective
configuration in the base 126. The pair of electrical terminals 135
and 136 are extensions of the coil spring 122 and the rod/31
respectively. The terminals 135 and 136 may be formed and treated
in conventional well known manner, to provide dirt and water
resistant terminals which can be free of short circuiting and the
like. The impact sensors can be permanently disposed behind
bumpers, in door panels, and in other necessary positions on
vehicles.
Further, a second carbon dioxide containing tank 5 or the like,
together with the system firing mechanism 6", without the magnesium
pyrotechnic composition, may be installed in the vicinity of the
gasoline tank of the vehicle, as in the car trunk or the like.
Typically, an impact sensor 130 or the like may be installed at the
rear of the car, such as on or adjacent to the rear bumper. On
signal from the sensor 130 that an impact has taken place in the
rear of the vehicle, the firing mechanism 6" can be operated,
ejecting liquid carbon dioxide into the vicinity of the gasoline
tank. The carbon dioxide will then vaporize and prevent or
extinguish any fire generated by a ruptured gasoline tank.
The personnel restraint system taught in this invention is
particularly suitable for automobiles, trucks, and other road
driven motor vehicles subject to accidents. It can likewise have
application to other personnel carrying vehicles such as speed
boats, airplanes, and the like, by utilizing impact sensors
particularly suited for the potential accident impact
parameters.
In order to promote the safety and well being of the occupants of
the motor vehicle, the personnel restraint system 1 should be
essentially sold, installed and maintained as a single use
disposable system. This mode of service requires that the system
should be installed in the motor vehicle as a sealed unit, with a
wire seal on the duct system cover 4 or the like, the seal to
clearly indicate whether the duct system has been tampered with.
After an accident it is proposed that the complete tank 5 and
firing mechanism 6 be returned to a factory for rebuilding, and
that a new unit be installed. Likewise the impact restraint bag 23,
or the like, should be disposable and thrown away with its carrying
case after a single accident, for the frangible hinge will prevent
the case from being easily re-used. In this manner it is possible
to maintain safety standards. A new impact bag contained in a
sealed carrying case would then be reinstalled in the vehicle. The
personnel restraint system is tamper resistant in the sense that
the system can be fabricated and installed with technique that
will, on inspection, clearly indicate that the system has been
tampered with.
Many modifications and variations of the improvement in the
personnel restraint system may be made in the light of the
teachings disclosed herein. It is therefore understood that within
the scope of the appended claims, the invention may be practiced
otherwise than as specifically described.
* * * * *