Note: Descriptions are shown in the official language in which they were submitted.
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BACRGROUND
Field of Inve~tion
The present invention relates to safety apparatus for
protecting the head of an occupant seated directly aft of
bulkhead structures in normal, utility, commuter and transport
category aircraft. More specifically, it relates to an inflat-
able bolster system that reduces the extent and severity of
injuries sustained during a crash by cushioning the head from
direct impact with the bulkhead structure.
~aak~roun~ of the Invention
Conventional lap belts are used to restrain occupant~
of aircraft during crashes and periods of abrupt acceleration or
deceleration. However, the protection provided by lap belts for
occupants seated directly aft of bulkheads is inadequate. For
the purpose of this discussion, bulkheads are wall-like struc-
tures aboard aircraft, such as structural bulkheads, compartment
partitions, and the walls of lavatories or galleys. The Federal
Aviation Administration (FAA) and its International counterparts
have recognized that occupants seated at these positions are most
vulnerable during a crash with respect to head injury. The
larger distance between the seat and the bulkhead allows the
occupant's head to impact the bulkhead with a larger velocity
than the heads of those sitting directly behind other seats. The
larger velocity results in a greater impact that inflicts more
serious injuries. Occupants seated in bulkhead rows are more
likely to suffer serious or fatal head injuries than other occu-
pants~
The FAA has addressed this particular head strike
problem by establishing new seating requirements under Federal
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Aviation Regulations (FAR's) 25.562 and 23.562. These
regulations set new head injury standards for normal, utility and
commuter category airplanes certificated after Sleptember 14, 198
and for transport airplanes certificated after June 16, 1988.
Additionally, a retrofit of in-service airplanes is anticipated
to meet these requirements.
Specifically, FAR's 25.562 and 23.562 require that
occupants be protected against serious head injuries caused by
impact against broad interior surfaces during a crash. These and
other regulations also address protection from low impact, cos-
metic head injuries that may involve irreversible nerve damage or
permanent disfigurement. In the event of a crash, the regula-
tions generally allow a three-inch, permanent, forward displace-
ment of the seating structure. It follows that during a crash,
the dynamic seat deflection can exceed three inches. This
deflection thus creates an even larger head strike envelope in
which the heads of occupants sitting in bulkhead rows can suffer
an even greater risk of impact.
Thus far, no newly certificated airplanes have met
either FAR 25.562 or 23.562 head injury criterion for bulkhead
seating. However, the Canadair Regional Jet and British Aero-
space J-41 type certificates were recently issued, each with a
one-year waiver for the head injury criterion.
Several countermeasures have been suggested by seat and
airframe manufacturers to solve the bulkhead problem including:
bulkhead air bags, additional bulkhead padding, shoulder
restraints for these positions, bulkheads with partially
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frangible panels, the removal or relocation of a row of seats aft
of each bulkhead, and special seats that rotate the occupant's
legs upward in the event of a crash. All of these potential
solutions suffer serious drawbacks.
The first countermeasure, bulkhead air bags, depending
on configuration, may have a number of disadvantages. First,
they are a potential cause of injury, rebounding the occupant
back into the seat with excessive force. Second, they are
particularly dangerous to occupants assuming a typical crash--
braced position, in which the head is above or on the knees.
~hird, bulkhead air bags are designed such that they will strLke
an occupant whether or not the head would come in contact with
the bulkhead. For example, a small child is not in danger of
impacting with the bulkhead structure, yet he or she would be
needlessly struck by the inflating air bag. Fourth, when the air
bag deploys, it may produce excessive noise and smoke. This is
likely to alarm occupants. Finally, large, post-deployed air
bags potentially impede emergency egress.
The second countermeasure, padding the bulkhead, also
has severe drawbacks. First, a great deal of energy absorbing
material would be needed to effectively pad the bulkhead. Thus,
a great deal of occupiable space (i.e., six inches) would be
eliminated. Additionally, energy absorbing padding may increase
the frequency or severity of neck injuries.
The third option proposes the addition of shoulder har-
nesses for the occupants of bulkhead rows. The major drawback of
this countermeasure is the negative impact on passenger percep-
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tion. Occupants will perceive a safety difference according toseating location.
The fourth option proposes bulkheads designed with
frangible panels that allow occupants' heads to partially pene-
trate or punch through the structure. Although this solution may
reduce impact head injury, the frangible panels have the poten-
~ial to inflict cosmetic injuries involving irreversible nerve
damage or permanent disfigurement. This type of injury is more
likely to occur during the rebound phase of the crash.
The fifth solution proposes to increase seat setbac]c
from the bulkhead to a distance that would preclude head impact.
Moving the bulkhead seats would require the repositioning of all
the aircraft seats, as well as the removal of some seats
entirely. This solution would result in lost passenger revenues
for the airlines.
Finally, designing a special seat for these bulkhead
positions offers an unproven solution. Seat manufacturers have
suggested a seating structure with a seat pan that rotates the
occupant's legs upward during the crash. Although some initial
test results have been positive, the design has not been proven
effective in a crash environment.
In view of the potential problems with the proposed
countermeasures, effective head strike protection for seating
directly aft of bulkheads must provide adequate energy absorption
for the head region, while not creating a more hazardous environ-
ment for occupants regardless of body position or occupant size.
In addition, the system should neither alarm nor create negative
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passenger perceptions, inflict serious cosmetic injuries, impede
emergency egress, or require excessive space or cost.
8~ARY OF TlI13 }NVENTION
The present invention comprises an inflatable bolster
system whose bladder member(s) are stowed within a lightweight
frame that is mounted to the bulkhead of an aircraft.
The bolster is a continuous cushion that can be
partitioned into a number of separate bladders or cells. There
is no gas exchange between cells. The number of cells is
determined by the number of seats in the row directly aft of a
particular bulkhead. Generally, there is one cell for each seat.
This multi-celled configuration increases the stability and
effectiveness of the bolster and allows the system to be con-
veniently customized for a particular aircraft seating con-
figuration.
The bolster apparatus is connected to a crash sensor.
When a collision occurs, the sensor sends an electrical signal to
gas generators in the bolster, igniting the generators and thus
inflating the cell or cells. The gas generators are located
directly behind the bolster cell(s) and are integrated into the
bolster structure. Each cell may have more than one gas
generator.
Each bolster cell contains a number of internal webs.
The internal webs run both horizontally and vertically and con-
tain a number of openings or holes that allow gas to circulate
within each cell. The webs thus define a number of smaller
compartments within each cell. When the bolster is impacted by a
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body part, the holes in the internal web structure restrict the
speed of gas circulation within the cell, thereby improving the
performance of the bolster. The number of internal webs and
internal web openings can be varied in order to customize the
impact absorbing profile of the bolster. The internal web
structure also results in the inflated bolster having an "air
mattress-like" appearance.
The generated gas inflates the individual cells simul-
taneously. As gas flows into the cells, the bolster deploys from
its stowed position. In the fully deployed state, the bolster
forms an "air" cushion that extends approximately 12 inches out
from the bulkhead surface. The inflated bolster protects the
occupant's head from direct and excessive impact with the bulk-
head surface.
When used in conjunction with conventional lap belts,
the inflated bolster provides an effective strike protection
system that meets the head impact criterion of FAR's 25.562 and
23.562. It functions by distributing load over the entire
contact area of the occupant's head. The bolster is positioned
at an average seated head-level that provides head strike pro-
tection for a wide range of occupant sizes (i.e., a 95~ male down
to a small child). Additionally, the bolster provides strike
protection for the upper torso and upper extremities of some
laryer occupants.
The bolster has a number of advantages over conven-
tional air bag devices. First, it is much smaller and can deploy
at a much slower velocity. This means that the violent "punch"
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or abrupt acceleration that is often imparted by air bags (on the
occupant) can be avoided. Second, unlike conventional air bags,
the bolster is designed to deploy without striking the occupant.
This avoids unnece sary air bag inflicted injuries. It is also
less hazardous for occupants that have assumed a crash-braced
position. Third, the inflating bolster is a smaller device that
preferably uses an energetic, smokeless propellant. Therefore,
it produces significantly less noise and smoke than air bags,
which is critical for occupant composure and orderly post-crash
egress. Finally, the inflated bolster will not significantly
impede emergency egress because it does not hang to the floor, as
would large air bags.
An additional advantage of this system over other
devices is that it will not likely cause cosmetic injuries
involving irreversible nerve damage or permanent disfigurement.
It is also an economically feasible solution that requires
minimal space when stowed. Finally, it will have little or no
effect on passenger safety perception because its system com-
ponents are relatively concealed.
The undeployed bolster assembly is unobtrusive,
extending approximately one inch out from the surface of the
bulkhead. Pref0rably, it will protrude less than one inch. ln
the undeployed state, the bolster is concealed by a protective
cover that provides a durable and aesthetically pleasing package.
The fabric chosen for the cover can be coordinated to match the
interior of the airplane. In the event of a crash, the outer
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layer of the protective cover separates from the bulkhead under
the force of the inflating bolster.
The bolster system is a totally self-contained system
that can be installed during manufacture or be retrofitted into
in-service airplanes. The system is complete with its own
battery unit, requiring no integration with the aircraft's exist-
ing electrical system.
The durable housing that contains the crash sensor also
contains the battery unit. Generally, the crash sensor/diagnos-
tictbattery unit is mounted at the seat track-level in order to
accurately detect crash impacts to which the occupant is expo~ed.
The sensor/diagnostic/battery unit ~an be mounted at the base of
the bulkhead on either side of the structure or at some other
proximate location. The sensor/diagnostic/battery unit also
includes a diagnostic means for checking the integrity of the
electronic circuitry and the battery charge.
Accordingly, it is an object of the present invention
to provide a protective apparatus, used in conjunction with
conventional lap belts, that inflates to protect the head and
face of a restrained, seated occupant of a transport vehîcle such
as an aircraft from excessive impact with the bulkhead structure
during a crash.
It is another object of the present invention that
provides an inflatable bolster that is not potentially dangerous
to occupants assuming a typical crash position.
It is another object of the present invention to pro-
vide an inflatable bolster that in the deployed and undeployed
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states does not obstruct emergency exits or impede passenger
emergency egress.
It is another object of the present invention to pro-
vide an inflatable bolster system that attaches to the bulkhead
and provides convenient access to the seat.
It is another object of the present invention to pro
vide an inflatable bolster system that is self-contained, re~uir-
ing no integration with the vehicle's electrical system.
It is another object of the present invention to pro-
vide an inflatable bolster system that does not exert excessive
force on the occupant's head upon inflation.
It is another object of the present invention to pro-
vide an inflatable bolster system that provides a head strike
protection system that protects the occupant from cosmetic head
injuries involving irreversible nerve damage or permanent dis-
figurement.
It is another object of the present invention to pro-
vide an inflatable bolster system that provides a head strike
protection system that can be customized for a particular bulk-
head seating configuration.
It is another object of this invention to provide an
inflatable bolster system with a sensor/diagnosticjbattery unit
located to provide convenient access to the seat.
It is a further object of the present invention to
provide an inflatable bolster system that does not have a sig-
nificant negative impact on passenger safety perception.
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It is another object of the present invention to pro-
vide an inflatable bolster system that provides a head strike
protection system that does not unduly alarm the occupants by
producing excessive smoke or noise upon deployment.
It is another object of the present in~ention to pro-
vide an inflatable bolster system that provides a head strike
protection system that is cost effective.
These and other objects are described in greater detail
in the detailed description, the appended drawings, and the
attached claims.
DB8~RIPTION OF THE DRAWINGB
Figure 1 shows the present invention installed in a
typical transport aircraft bulkhead with portions being
broken away to show underlying features.
Figure 2a shows the present invention in the uninflated
state with respect to seated occupants.
Figure 2b shows the present invention in the inflated
s~ate with respect to seated occupants.
Figure 3 is a cross-sectional view of the inflated
bolster.
Figure 4 is a detailed view of a web internal to the
bolster.
DETAILED DE~C~IPTION OF T~E INVENTIO~
The preferred embodiment of the present invention is
shown in Figures 1-3. The inflatable bolster system 8 of the
present invention is shown in the uninflated state. It comprises
inflatable bolster 1, gas generators 2, frame structure 3, crash
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sensor/diagnostic/battery unit 6, as well as cover 4, electrical
cable 7, and mounting devices 5. The present invention is shown
as being attached to a typical aircraft bulkhead. The invention
is designed to be used in normal, utility, commuter and transport
category aircraft in which passengers are seated directly aft of
the bulkhead structures. The present invention can also be used
in other types of vehicles such as trains, buses, ships or boats.
Bolster 1 can be made up of several distinct cells.
Figures 1, 2a, 2b and 3 illustrate a bolster system having two
cells to accommodate a row containing two seats. Other bolsters
can have multiple cells or as few as one cell in order to
customize the system for a particular seating configuration.
Generally, the bolster contains as many cells as there are seats
in a particular row. Each bolster cell has at least one gas
generator 2 integrated into its rear wall for in~lation purposes.
Inflatable bolster 1 can be formed from an impregnated
fabric, such as nylon coated on both sides with neoprene, that is
relatively impervious to gas. The selected material must meet
FAA flammability requirements. As shown in Figure 1, undeployed
bolster 1 is contained within a frame structure 3. The preferred
method for stowing the bolster within frame 3 is by aligning the
front wall of the bolster directly over the rear wall and folding
the side walls between them in an accordion manner. As stowed,
bolster 1 is concealed under a protective cover 4. Frame struc-
ture 3 is made of a lightweight, durable material such as
aluminum. Frame structure 3 is basically a rectangular frame
with vertical cross members (not shown) onto which gas generators
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2 are suitably attached. The cross members are flush with the
outer frame members. Mounting brackets 5 attach frame structure
3 to bulkhead 9. The bolster/frame assembly is positioned on the
bulkhead at seated head-level. The undeployed bolster assembly
extends out from the bulkhead approximately one inch or less. It
extends up the bulkhead approximately 24-30 inches. Its width is
determined by the number of cells in a particular bolster and the
anticipated range of occupant motion.
When inflation is initiated, the internal gas pressure
of bolster 1 forcibly separates cover 4 from frame 3, and the
bolster inflates. In a first embodiment, cover 4 is bonded to
the front surface of bolster 1, allowing cover 4 to deploy along
with the bolster. In this case, the cover material may enhance
the energy-absorbing function of bolster 1.
In a second embodiment, cover 4 includes a network of
weak seams along which cover 4 ruptures, thus allowing bolster 1
to inflate. The preferred rupture pattern minimizes the trajec-
tory of the cover material in the direction of the occupant. It
also minimizes the amount of cover fabric that remains in the
vicinity of the emergency exits following deployment, thus
minimizing egress problems. For example, four flaps can be
formed from Gover 4; two large flaps and two small flaps. Of the
larger flaps, one would deploy downward and the other outward,
away from the nearest aisle. Of the smaller two flaps, one would
deploy upward and the other outward, toward the nearest aisle.
This last flap could also be designed to soften the corner of the
bulkhead structure.
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Smokeless propellants are preferred. Preferably,
highly energetic propellants such as nitrocellulose or hybrid
inflators using pyrotechnic hezters and argon gas would be used.
Propellants using sodium azide, such as those used by U.S. auto-
motive air bag systems, would preferably not be used.
Figure 2b shows bolster 1 fully deployed. Fully
deployed bolster 1 bulges out approximately 6 to 18 inches from
bulkhead 9 to provide an effective energy-absorbing cushion for
the occupants' heads. Inflatable bolster system 8 takes approxi-
mately 30 to 40 milliseconds to inflate, while bulkhead head
impacts generally occur in 70-90 milliseconds. The internal
pressure of bolster 1 is comparable to the internal pressure in
conventional air bags. The internal pressure is generally less
than 2 psi. The preferred internal pressure is 1 psi or slightly
lower. ;
Figure 3 is a cross-sectional view of inflated
bolster 1. Figure 3 shows that each bolster cell has outer walls
10 that prohibit gas ~rom passing between cells. Internal webs
11 are positioned both horizontally and vertically, further
dividing each bolster cell into smaller compartments. These
internal webs give bolster 1 an air mattress-like appearance, as
shown in Figure 2b. More importantly, internal webs 11 provide
bolster 1 with improved stability.
Figure 4 shows a detailed view of internal web 11.
Each internal web includes openings or holes 12 that permit gas
to circulate within a particular cell. Upon impact, gas is
forced to disperse from the impacted cell compartment. However,
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holes 12 limit the speed of gas circulation, thereby providing
more efficient impact protection. The number and size of holes
in internal web 11 can be varied to optimize system performance
for a specific aircraft configuration. Smaller holes are pre-
ferable because they allow the use of a bolster having a smaller
internal pressure. This is possible because the smaller holes
further restrict gases from dispersing away from the area of
impact, thus causing a local area of higher pressure that is
needed for impact protection. This can also reduce the amount of
propellant that is required because the bolster requires less
gas. Generally, the larger the distance between the seating
structure and the bulkhead, the more gas pressure is needed to
provide adequate impact protection, therefore less holes or
smaller holes are preferred. However, when the distance between
the seating structure and the bulkhead reaches a certain point,
head impact with the bulkhead structure will no longer occur.
~ olster 1 is able to distribute the force of the impact
over the entire contact area of the occupant's head. After
inflation, bolster 1 will remain sufficiently inflated to proYide
additional protection in the event of multiple impact crashes.
Figures 1, 2a, 2b and 3 illustrate a bolster having an
internal web system that includes three horizontal webs and one
vertical web per cell. Figure 2b shows that this specific
internal web configuration produces a bolster having eight tufted
surfaces per cell. The number of internal webs can be varied in
order to optimize the impact absorbing characteristics of bolster
1. There are a number of facts that can influence the number of
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webs or holes in the internal web structure, such as the inflated
gas pressure of the bolster and the seat setback from the bulk-
head.
As shown in Figure l, gas generators 2 are connected by
electrical cable 7 to crash sensor/diagnostic/ba1:tery unit 6.
When the crash sensor detects an impact, it sends a signal
through electrical cable 7 to the initiators in gas generators 2.
The initiators then ignite, causing the propellant to burn, thus
producing gas.
Following inflation, the gas in bolster l is retained
by venting means 13 (shown in Figure 3) that is initially closed.
When the occupant strikes the inflated bolster, the deformation
of bolster l causes the vent to open. This provides an energy
absorbing means that prevents the occupant's head from rehounding
off bolster l with excessive velocity. Venting means 13 opens
when it senses bolster deformation and/or when the internal
pressure of bolster l increases by a given increment ~e.a., by l
or 2 psi). After contact, the vent may reclose to provide resi-
dual protection from subsequent impacts. Each bolster has at
least one vent located in the bottom portion of the bolster.
Crash sensor/diagnostic/battery unit 6 contains a crash
sensing device and a long-life, replaceable battery pack. It is
best attached to a relatively stiff structure at seat track-level
by solid connections. A solid connection is required in order
for the crash sensor to accurately detect impacts. The crash
sensor determines a crash environment when certain acceleration
and velocity change criteria are met. These criteria can be
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fined tuned for different bulkhead locations aboard the airplane
and for different airplanes. Inflatable bolster system 8 is
preferably powered by long-life batteries, such as lithium
batteries that have a life expectancy of five to ten years. The
bolster system requires no integration with the aircraft's elec-
trical system, although it could be adapted to use the existing
electrical system, if desired. Crash sensor/diagnostic/battery
unit 6 also includes a means for checking the integrity of the
electronic circuitry and ~he battery charge.
Although mounting brackets 5 and electrical cable 7 are
shown clearly in Figure 1, these components would normally be
concealed by the fabric or material that covers bulkhead struc-
ture 9. Electrical cable 7 could also be located on the opposite
side of the bulkhead. Crash sensor/diagnostic/battery unit 6 can
also be mounted on the opposite side of the bulkhead structure to
minimize passenger interference. Figures 2a and 2b illustrate a
preferred inflatable bolster system 8 whose electrical cable,
mounting brackets, and crash sensor/diagnostic/battery unit are
concealed accordingly.
The foregoing disclosure o a preferred embodiment of a
preferred invention has been presented for the purposes of illus-
tration and description. It is not intended to be exhaustive or
to limit the invention to the precise form disclosed. In par-
ticular, the present invention may be used in vehicles other than
aircraft, such as in trains, buses, ships and boats. Many varia-
tions and modifications of the embodiment described herein will
be obvious to one of ordinary skill in the art in light of the
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above disclosure. The scope of the invention is to be de~ined
only by the claims appended hereto.
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