.
`
`United States Patent [191
`Kithil
`
`|l|||llllllllllllllllllllllIllllIllllllllllllllllllllllllllllllllllllllllll
`[11] Patent Number:
`5,366,241
`[45] Date of Patent:
`Nov. 22, 1994
`
`USO05366241A
`
`[54] AUTOMOBILE AIR BAG SYSTEM
`__
`_
`_
`_
`[76] Invento? P111111) W- Kl?lll, 1274 Vallec?a Dre
`Santa Fe, N. Mex. 87501
`1 N 130 089
`[21] App ‘ o"
`’
`[22] Filed:
`Sep. 30, 1993
`
`' ' ' ' ' ' ' ' ' '-;-,;6;;-3~5_B268%Ij,23g/
`C015 ' ' i '
`. .
`. .............................. ..
`,
`280/736,
`
`5,058,921 10/1991 Cuevas .............................. .. 280/741
`5,071,160 12/1991 White et a1. ..
`5,112,134 6/1992 Mattes ............................... .. 280/735
`
`OTHER PUBLICATIONS
`D. S. Breed et al, “A critique of single point sensing”,
`SAE Int’l Re ort No. 920124, Feb. 1992, p. 51.
`PARS D p A h & D Unkn
`ocument, at or
`ate
`own.
`D. 5. Breed et al, “A complete frontal crash sensor
`System_l,,’ SAE In? Report NO‘ 930650’ Mar‘ 1993,
`
`[58] Field of Search ............. .. 280/728 A, 729, 730 R,
`280/735, 736, 739, 741, 742
`References Cited
`
`[56]
`
`pp' 119-121’ 124-132'
`Primary Examiner—Kenneth R. Rice
`Attorney, Agent, or Firm—Robert W. Harris
`
`U.s. PATENT DOCUMENTS
`280/735
`3 629 816 12/1971 Gmund
`"""""""""""" " 280/731
`3’752’501 8/1973 Daniel
`3:774:936 11/1973 Barnett et a1"...
`...... "280/730 R
`3,394,750 7/1975 Eckds _ _ _ _ _ _ . ,
`_ _ _ __ 2g0/730R
`3,900,210 3/1975 Lohr e1 31, _
`_______ ,_ 280/729
`3,917,023 11/1975 De Rosa ....... ..
`280/730 R
`4,006,918 2/ 1977 MacFarland . . . . . . .
`. . . . . . . .. 280/729
`
`ABSTRACT
`[57]
`An overhead-mounted air bag deployment system, hav
`ing overhead sensors and a microprocessor to measure
`and analyze Passmféer 1110mm as Well as Vehicle decel
`eration, for consideration by the microprocessor in
`deciding whether to deploy the air bag, so as to deal
`with case-to-case variations in passenger motion. The
`system also has both a warning light and a warning
`
`4,130,298 12/1973 51131111116556)’ - - - - - -
`' e - ~- 280/730 R sleeve on the steering wheel, to discourage the driver
`1213/
`llgi‘r’eis efft 31' """"""" "
`from remaining in a position involving an increased risk
`4’536’O08 82985 Broil? 1; ' ‘ ' ' ' ' ‘ ‘
`' ‘ ' ' ' "580/7240 R
`of injury, and has an automatic bag release means to
`4,565,535 1/1986 Tassy
`‘I...- 280/728 A release the air bag and free the Passenger when the
`4,985,835 1/1991 Sterier etal.
`364/424.05
`°°11151°n Is Over
`
`5,033,390 7/1991 Minert et a1. . . . . . .
`
`. . . . . . . .. 280/742
`
`5,039,035 8/1991 Fitzpatrick .................... .. 280/730 R
`
`13 Claims, 6 Drawing Sheets
`
`4
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`8 IO 6
`i
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`US. Patent
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`Noy. 22, 1994
`Nov. 22, 1994
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`5,366,241
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`Nov. 22, 1994
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`U.S. Patent
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`Sheet 6 of 6
`Sheet 6 of 6
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`US. Patent
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`Nov. 22, 1994
`Nov. 22, 1994
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`1
`
`AUTOMOBILE AIR BAG SYSTEIVI
`
`5,366,241
`2
`body. Such a protective reaction may vary greatly from
`one passenger to another, and may be greatly reduced
`or wholly absent if the collision is too sudden, so that
`the passenger has no time to react, or if the passenger is
`quite intoxicated. Also variation of the crash intensity
`by itself will cause considerable variation in passenger
`acceleration. So there is a need for systems which mea
`sure the position vs. time of the passenger, and analyze
`that information in making the yes or no decision on air
`bag deployment. Although such systems are known, as
`described in documents ?led with applicant’s Informa
`tion Disclosure Statement, applicant is not aware of
`such a system employing overhead sensors, as in the
`present invention. Overhead sensors offer an advantage
`over those previously known systems having sensors
`located in front of the passenger, as in air bag systems
`and sensors mounted on the steering column, for which
`the sensors will at times by blocked from operating by
`the hands and/or forearms of the driver. Also such
`systems may not measure the change of position of most
`critical body parts, such as the head, but rather less
`critical portions, such as the torso.
`The prospect for successful operation of an air bag
`system in a particular crash may depend not only on the
`passenger’s initial position, and the motion of the pas~
`senger’s body as a whole, but may also depend on the
`height of the passenger, which affects the position and
`motion of the passenger’s head during the collision. The
`head of the passenger is of course particularly vulnera
`ble to serious and often fatal injury from collision with
`hard surfaces during a collision. So the present inven
`tion includes sensor means to determine the height of
`the passenger’s head, as one important initial position
`parameter to be considered by the system’s micro
`processor.
`In order to discourage a passenger from riding in a
`position causing an increased risk of injury, such as a
`position too far forward, it is desirable to warn the
`passenger against such unsafe positions. It has been
`known to have a warning light for this purpose, where
`a position sensor detects this condition. However, a
`warning light alone may not be noticed, and the present
`invention also provides an additional means, for the
`driver, namely a tactile and printed warning sleeve on
`' the steering wheel.
`It is also desirable to have a means for the air bag to
`be automatically released after the collision is over, so
`that the bag can de?ate and free the passenger to see
`and be able to bring the vehicle to a stop if it is still in
`motion, and be able to exit the vehicle and/ or render aid
`to other passengers. This could be particularly impor
`tant if another passenger is more seriously injured and
`needs immediate emergency rescue personnel to be
`called to the accident scene, or if a tire has started as a
`result of the collision. The present invention meets this
`need by providing an air bag release means which func—
`tions automatically.
`Since the design of automotive air bag systems con
`tinues to evolve, as more knowledge is gained about the
`dynamics of crashes, including problems associated
`with variations in passenger motion during a crash,
`there is a need, for crash investigation purposes, for a
`system which can record the vehicle and passenger
`motion during the crash process. This need is met by the
`present invention, through the provision of recording
`means connected to the sensors which detect vehicle
`and passenger motion.
`
`50
`
`BACKGROUND OF THE INVENTION
`The present invention concerns systems for deploy
`ment of air bags during vehicle crashes. More particu
`larly it concerns systems in which the system operation
`is affected not only by information about the decelera
`tion of the vehicle caused by crash forces, but also mea
`sured data concerning the passenger, including height,
`position and motion of the passenger, so that the system
`will operate in a manner to minimize the risk of serious
`injury to the passenger. It is also concerned with means
`to warn the passenger about the enhanced risk of serious
`injury which can occur during air bag deployment if the
`passenger is out of proper position in relation to the air
`bag system, and means to automatically release the
`passenger from the air bag restraint and regain passen
`ger visibility when the collision is over.
`20
`Automobile air bag systems are a well known means
`of attempting to reduce the likelihood of serious injury
`to passengers in collisions. These systems are designed
`to very quickly in?ate an air bag in front of a passenger
`during a collision, so as to hopefully prevent the passen
`25
`ger from colliding with hard objects in the passenger
`compartment interior, particularly the steering column
`and/or the dashboard. As described in documents ?led
`with applicant’s Information Disclosure Statement, the
`system typically senses that the vehicle is involved in a
`collision, by using an accelerometer to sense sudden
`deceleration of the vehicle. Rapid in?ation of the air
`bag may be obtained by electrical ignition of a pyro
`technic substance which rapidly generates a volume of
`gas sufficient to in?ate the air bag, or by means of com
`pressed gas stored in a chamber which is part of the air
`bag system.
`The performance of an air bag system, in terms of its
`success or failure in preventing serious passenger injury,
`may be critically dependent on facts concerning the
`initial position and subsequent motion of the passenger,
`which are not made known to the system by an acceler
`ometer which senses deceleration of the vehicle as a
`whole. For example, if the passenger is seated too far
`forward, occupying the space into which the air bag
`will deploy, the passenger may, ironically, be seriously
`injured by the deployment of the air bag intended to
`prevent passenger injury. So there is clearly a need for
`passenger position sensing apparatus, which can pre
`vent air bag deployment when the passenger is already
`too far forward when the collision begins.
`But even if the passenger is not too far forward at the
`beginning of the collision, the passenger will tend to
`move rapidly forward, relative to the vehicle, as the
`vehicle rapidly decelerates, and will tend to move into
`the air bag deployment space, at least in the case of
`55
`forward collisions, and may be too far into the air bag
`deployment space, before the completion of air bag
`deployment, to escape injury from the air bag deploy
`ment. There are a number of factors which may
`strongly in?uence the forward motion of the passenger,
`60
`in addition to initial position. The relative forward mo
`tion of the passenger will depend strongly on whether
`the passenger has secured a seat lap belt and/0r shoul
`der harness prior to the collision. The passenger’s mo
`tion may also be in?uenced somewhat by the strength of
`65
`any tensing up reaction the passenger has to the colli
`sion, i.e. instinctively pushing forward with the feet
`against the ?oorboard to restrain forward motion of the
`
`35
`
`40
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`3
`Depending upon the nature of the collision, there
`may be a need for an air bag in which the total cushion
`ing time can be stretched out, to a longer time than that
`which could be obtained with a single chamber air bag.
`Applicant believes that the present invention may be
`useful in this respect, through the provision of a multi
`chamber air bag, in which the gas ?ows sequentially
`between various chambers of the air bag.
`
`10
`
`5,366,241
`4
`lowing purposes: (1) Use actual measured data on pas
`senger height, position and motion, in making the deci
`sion as to whether or not the air bag should be de
`ployed, and if deployment is desired, when it should
`occur; (2) provide overhead passenger position sensors,
`as opposed to sensors mounted on the steering wheel,
`door or front panel assembly as in some other systems,
`so as to avoid the problem of sensor blockage by the
`hands of the driver; (3) warn the passenger, in more
`than one manner, against being in a position which
`would risk injury from air bag deployment; (4) provide
`automatic release of the air bag after the collision, to
`free and regain visibility for the passenger; (5) deploy
`the air bag in a rapid, efficient manner; (6) provide
`means to record passenger motion just before and dur
`ing a crash event, for crash investigation purposes; (7)
`attempt to extend cushioning time, by use of a multi
`chamber air bag, and by possible sequential ignition of
`in?ators; (8) minimize the expense of retro?tting the
`system to an existing automobile having no air bag
`system, by use of overhead-mounted components, as
`opposed to components mounted forward of the driver,
`as in the steering column assembly; (9) provide dual air
`bag in?ators, to allow for possible sequential ignition at
`different times, to prolong the ?ow of gas into the air
`bag, thus possibly extending the cushioning time; and
`(10) to provide a sun visor mounted above the air bag
`in?ation module, which is attached by a rolling hinge
`and may be deployed by pulling it down.
`
`20
`
`25
`
`30
`
`55
`
`SUMMARY OF THE INVENTION
`The invention is an overhead-mounted system, in
`cluding means for deploying an air bag. The system has
`sensors to sense the position and acceleration of the
`occupant’s head, and to sense deceleration of the vehi
`cle; outputs of the sensors are analyzed by a micro
`processor mounted in the roof area with the sensors,
`above the occupant, possibly but not necessarily in a
`longitudinally mounted tunnel. A warning light is
`mounted on the tunnel housing, which is lit by a signal
`from the microprocessor if the occupant is not in proper
`position for safe deployment of the air bag. In the event
`of a crash, based upon comparisons of the accelerations
`of the occupant vs. the passenger compartment, and of
`the vehicle vs. the Earth, and the initial position of the
`occupant, the microprocessor determines whether the
`accelerations indicate a crash of suf?cient severity for
`deployment of the air bag, and if so determines optimum
`deployment time. If deployment could not occur in time
`to protect the occupant, then no deployment occurs.
`The microprocessor also contains a recording means,
`for recording the last 10-15 seconds of signals from the
`sensors just before and during a crash, for possible later
`use in crash investigation. A ?ring signal from micro
`processor activates ?ring squibs which ?re two pyro
`technic in?ators, which employ sodium azide or other
`in?ator formulations, housed in the ends of a bilateral
`in?ator tube transversely mounted to the vehicle ceiling
`at the front end of the tunnel, forming a T with the
`tunnel. Combustion of the in?ators releases gas, which
`?ows initially through two ?lter/cooling chambers in
`the ends of the in?ator tube, each such chamber having
`screening means to capture slag particles, although the
`?lter/cooling chambers and screening means may not
`be necessary for some in?ator compositions, and thence
`to a downwardly-pointing nozzle at the middle of the
`45
`in?ator tube, with the two ?lter/cooling chambers
`being separated by gas diverters, which force the gas
`down into the nozzle. The multi-chamber air bag, at
`tached to the nozzle by a releasable clamp, breaks out of
`a breakaway opening in a cover, upon deployment. The
`50
`gas enters the air bag via an in?ation tube. After the gas
`has exited the nozzle and in?ated the air bag, heat gen
`I erated by the in?ator combustion expands a bimetallic
`element in the releasable clamp, and residual gas pres
`sure, automatically cause release of the air bag from the
`nozzle, so as to free the occupant from the obstruction
`of the air bag, and regain his visibility. To prevent in
`jury to the occupant from gripping the top of the steer
`ing wheel at the time of deployment of the air bag, or
`from sitting too close to the steering wheel or otherwise
`being out of proper position, a tactile and printed warn
`ing sleeve is permanently attached to the top of the
`steering wheel, to warn the occupant against these and
`other hazards or limitations of the system, to supple
`ment the warning light feature.
`The purposes of the present invention include provi
`sion of an air bag deployment system having a combina
`tion of elements which will accomplish all of the fol
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a side elevational view of the system.
`FIG. 2 is view as in FIG. 1, on a somewhat larger
`scale,
`FIG. 3 is cross sectional view of the in?ator module
`and a portion of the in?ated air bag, as seen from the
`rear driver side).
`FIG. 4 is a view of the deployed air bag, as seen from
`the rear (driver side) of the vehicle.
`FIG. 5 is a sectional view of the air bag, for the sec
`tion 5--5 indicated in FIG. 4.
`FIG. 6 is a rear sectional view of the air bag module,
`showing the folded air bag, prior to deployment.
`FIG. 7 is a side sectional view of the air bag module
`in the undeployed con?guration as in FIG. 6.
`FIG. 8 is a graph showing the general nature of ex
`pected sensor responses for vehicle deceleration (solid
`curve) and acceleration of the head of a passenger
`(dashed curve), which is intended only to depict the
`qualitative nature of these curves, and is not based on
`any actual measurements.
`FIG. 9 is a perspective sectional view of the bimetal
`lic air bag release clamp, though the axis of the air bag
`in?ation nozzle, with the lower views in the ?gure
`showing a plan and a side elevational view of a strip
`having a bimetallic tongue.
`FIG. 10 is a sectional view of the air bag module, on
`a section normal to and bisecting the longitudinal axis of
`the module, with the air bag attached by releasable
`clamp, and the upper portion of the air bag.
`FIG. 11 is a side elevational view of the deployed air
`bag.
`
`60
`
`65
`
`DESCRIPTION OF THE PREFERRED
`EMBODIMENT
`Referring now to the drawings, in which like refer
`ence numbers denote like or corresponding elements, a
`hollow mounting tunnel 2 is secured to the interior roof
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`5,366,241
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`from various portions of the passenger’s head 26, and
`of the passenger compartment, parallel to the vehicle
`axis, and is located above the occupant, i.e. the driver
`other portions of the passenger’s body, to create a pro
`and/or the passenger. Mounted in mounting tunnel 2, is
`?le of distances from the various portions of the head or
`other body parts, to passenger sensor array 4. When
`a passenger sensor array 4, which contains one or more
`sensors for sensing the position and velocity of the
`passenger’s head 26 moves forward during a crash, this
`pro?le changes, since signals which formerly re?ected
`driver or other passenger, as further discussed below.
`Also housed in mounting timnel 2, is a vehicle acceler
`off the rear of the top of passenger’s head 26, now re
`ometer 6, also further discussed below, for sensing vehi
`?ect of‘!~ the seat back; and signals which formerly re
`?ected from the legs now re?ect from the passenger’s
`cle deceleration as in a crash; a microprocessor 8, con
`head 26. Comparison of the pro?les at various times
`nected by wires (not shown) to the outputs of passenger
`during a crash event, by microprocessor 8, allows for
`sensor array 4 and vehicle accelerometer 6, for analysis
`calculation of expected time of impact with steering
`of the output signals of these sensors, as discussed be
`low, and a backup battery 10, for backup electrical
`wheel 28, or the windshield.
`power for system operation; and wiring (not shown)
`The vehicle accelerometer 6 is a conventional accel
`connecting the vehicle electrical system to the air bag
`erometer, well known in the art, which measures the
`electrical system. Located on the bottom of the mount
`rate of deceleration of the vehicle, and produces an
`ing tunnel 2, is a warning light 12, activated by the
`output signal proportional to the vehicle deceleration,
`which signal is analyzed by microprocessor 8 as an
`system to warn the passenger against remaining in a
`position that is not suitable for proper system perfor
`indication of a crash event. The vehicle accelerometer 6
`may be, for example, but is not necessarily, a piezoelec
`mance, as further discussed below.
`At the forward end of mounting tunnel 2, and dis
`tric sensor, which produces an output signal propor
`posed at a right angle to said tunnel, forming a T there
`tional to the vehicle acceleration. See, e.g. US. Pat. No.
`with, is an air bag module 14, which houses a multi
`4,985,835, on the invention of Sterier et al, at Col. 1,
`lines 35-43. The microprocessor 8, analyzes the outputs
`chamber air bag 16, further described below, which is
`normally folded up within air bag module 14, supported
`of passenger sensor array 4, and vehicle accelerometer
`from below by a cover 18 having a breakaway portion
`6, to determine whether to deploy the air bag. The
`which will open to allow deployment of air bag 16; and
`output of vehicle accelerometer 6 is analyzed to deter
`an air bag in?ation module 20, further described below,
`mine whether the deceleration observed at various
`having pyrotechnic in?ators 22, which generate gas for
`times during the time interval 30 from beginning of the
`in?ation of air bag 16. A sunvisor (not shown) may also
`crash event, is large enough to indicate a crash, as op
`be attached to in?ation module 20 by a rolling hinge.
`posed to unusually strong brake application, or normal
`Depending on the sizes of the sensors and other compo
`road vibrations, potholes, or minor “fender benders”. If
`nents mounted on mounting tunnel 2, it may be possible
`the deceleration is large enough to indicate a crash, the
`deceleration is also compared by microprocessor 8 to
`to mount all of those components in a small sensor hous
`ing on the rear surface of in?ation module 20.
`known crash characteristics for the vehicle, so that the
`microprocessor 8 determines a parameter indicative of
`The passenger sensor array 4 contains one or more
`likely crash severity.
`sensors capable of sensing both position and velocity of
`the passenger, beginning with the initial passenger posi
`The microprocessor 8 also compares the values of the
`tion 24, indicated (FIG. 2) by both the longitudinal
`acceleration of the passenger’s head 26, relative to the
`position of the passenger’s head, and the height of the
`passenger compartment, and the vehicle deceleration
`40
`passenger, as indicated by the distance from the top of
`rate, as shown in FIG. 8, and also considers the initial
`passenger position 24, as to both head height and dis
`the passenger’s head 26 to the passenger sensor array 4.
`Because the passenger’s head 26 acts like an upside
`tance from the impact surface, to determine whether the
`air bag should be deployed, and, if the decision is to
`down pendulum in a crash, even if the passenger is
`deploy, determines the optimum ?ring time and se
`unrestrained, the passenger’s head 26 will be the ?rst
`part of the passenger’s body to experience violent for
`quence for pyrotechnic in?ators 22, in order to optimize
`system performance and minimize the risk of serious
`ward motion relative to the passenger sensor array 4.
`The motion of passenger’s head 26 thus gives the earli
`injury to the passenger. The vehicle deceleration rate,
`est indication of impending passenger contact with hard
`as sensed by vehicle accelerometer 6, functions as an
`interior surfaces of the vehicle. The passenger’s torso
`arming means, such that absent a suf?cient vehicle de
`celeration the air bag 16 will not be deployed, even if
`also moves, but due to greater mass and muscle tone,
`and presence of the arms on the steering wheel 28, and
`the signals from passenger sensor array 4 reveal head
`possible seat belt usage, the torso follows rather than
`motion indicative of a need for deployment. This is to
`precedes the passenger’s head 26. Thus head motion is
`prevent deployment from extraneous violent head mo
`the more reliable early indicator for passenger motion,
`tion, e. g. from a violent sneeze.
`for analysis of conditions for deployment of the air bag
`A more precise description of a suitable deployment
`to protect both the head and torso. The passenger sen~
`paradigm is as follows: The passenger sensor array 4
`makes multiple measurements of the “y” dimension
`sor array 4 may contain optical, ultrasonic, infrared
`and/ or microwave emission and absorption devices, as
`between passenger sensor array 4, and passenger’s head
`disclosed for example in the air bag deployment system
`26. The signals re?ecting these measurements are con
`veyed by wires (not shown) to microprocessor 8, which
`shown in the patent on the invention of Mattes, US
`conducts a pro?le of the passenger’s head surface, and
`Pat. No. 5,118,134, at Col. 3, line 50-Co1. 4, line 38, and
`FIG. 2, which disclosure is incorporated herein by this
`determines the x-axis location of the pro?le relative to
`the potential deployment path of air bag 16. This data is
`reference, capable of measuring both position and ve
`locity of the passenger, possibly employing more than
`sampled and recorded by microprocessor 8 for a short
`one type of physical process, depending upon the accu
`time (IO-l5 seconds), and then overwritten with newer
`racy of the position and velocity data desired. The pas
`data. During a crash, vehicle accelerometer 6 senses the
`crash pulse and conveys the deceleration vs. time values
`senger sensor array 4 emits signals which are re?ected
`
`65
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`abrade the hands or cause other injuries to the occu
`to microprocessor 8, which compares the values to
`pant. The warning sleeve 32 might alternatively be
`crash-indicative minimums for the vehicle type. If the
`replaced by a warning sign located on the hub of the
`acceleration pulse exceeds the minimums, the micro
`steering wheel 28, or at any other location in which the
`processor 8 allows ignition of the squibs to initiate de
`driver may be warned against improper body or hand
`ployment of air bag 16, if, within a suitable time win
`position. A suitable warning for the preferred embodi
`dow, the “y” dimensions create a pro?le indicating
`ment might read as follows: “Air bag design limitations
`forward movement of the passenger’s head 26 greater
`than speci?ed minimum velocity values. The minimum
`can be exceeded in frontal crashes over 35 mph, and air
`bag will not deploy. Lighted warning light indicates
`might be set for example, at a velocity of 10 mph, or
`limitations. Extend arms and sit well back from wheel to
`0.176 inches per millisecond. If the passenger’s head 26
`increase effectiveness of the system. Keep hands on
`moved a “trigger distance” corresponding to this veloc
`sides of wheel to prevent obstruction of air bag deploy
`ity (1.3 inches in less than 7 milliseconds), the micro
`ment. Always wear your seatbelt.”
`processor 8 would interpret this as the second necessary
`The in?ation module 20 is a linear bilateral module,
`condition to ignite the squib. Based on the actual X axis
`the main portion of which is cylindrical in form, and
`motion (in the longitudinal direction parallel to the car
`axis) the microprocessor 8 would calculate the expected
`contains two pyrotechnic in?ators 22, one on each side
`of in?ation module 20. Each of pyrotechnic in?ators 22
`arrival time of the passenger's head 26 at the deploy
`has a pyrotechnic composition containing sodium azide,
`ment path of the air bag 16, and knowing the in?ation
`response time, trigger the squibs accordingly. Under
`and which may also contain nitrocellulose. The pyro
`this paradigm the system would not deploy the air bag
`technic composition is one which burns to produce a
`large volume of gas. Ignition of pyrotechnic in?ators 22
`16 unless both the crash deceleration pulse and the head
`is accomplished by means of squibs 34, located in the
`motion exceeded the minima, and would not deploy
`ends of in?ation module 20, which squibs are low tem
`even then if the pro?le data indicated that the passenger
`perature pyrotechnic devices to activate burning of
`head position would be into or beyond the path of de
`pyrotechnic in?ators 22. The ?ring signals, to ignite the
`ployment of air bag 16, before the air bag could deploy.
`squibs 34, are communicated to squibs 34 by wires 36,
`The microprocessor 8 will also activate warning light
`which connect each of squibs 34 to microprocessor 8.
`12, independently of any crash event, if the data on
`Each of the pyrotechnic in?ators 22 communicates
`passenger position indicates that the passenger’s head 26
`through ports 38 with a ?lter/cooling chamber 40,
`is located too close to the air bag deployment path, so
`which conveys the generated gas toward the center of
`that the head would be in the path of deployment at the
`in?ation module 20, through screening means 42, in the
`maximum operating velocity of the system, estimated to
`be 35 mph.
`form of stainless steel mesh materials and screens, which
`screening means 42 captures and removes hot slag parti
`The microprocessor 8 will not deploy the air bag, if
`cles, generated in the burning of pyrotechnic in?ators
`the analysis indicates that the crash is low-speed, in
`22, from the ?owing stream of gas, before it reaches the
`volving low risk of serious injury, or if the analysis
`midportion of in?ation module 20. At the midpoint of
`indicates that the passenger is too far forward, so that
`in?ation module 20 is a downwardly-projecting nozzle
`the air bag cannot deploy in time and that attempted
`deployment not only would not prevent serious injury,
`44, to convey the gas, as it emerges from the ?lter/cool
`ing chambers 40, downward into air bag 16. Down
`but might actually cause additional injury from the
`wardly-sloping gas diverters 46 join at the midpoint of
`deployment itself, as the expanding air bag impacts the
`in?ation module 20, to divert the gas downward into
`passenger’s body. For example, if the driver is too far
`nozzle 44.
`forward, the air bag may come down on the top of the
`The air bag 16 is attached to nozzle 44 by means of a
`driver’s head, or behind the driver, pushing and trap
`releasable clamp 48. The releasable clamp 48 is a bime
`ping him against the steering wheel or windshield. Or
`tallic clamp, with a curved bimetallic tongue 50 at one
`the driver may be through the windshield before de
`45
`end thereof and a matching slot 52 at the other end
`ployment can occur.
`thereof, for receipt of bimetallic tongue 50. The interior
`The microprocessor 8 also contains a recording
`surface of releasable clamp 48 has an annular groove 54,
`means, to record the signals from the passenger sensor
`which ?ts over an outwardly protruding lip 56 in the
`array 4 and vehicle accelerometer 6 during the crash
`wall of nozzle 44, and which also holds a fabric ?ller
`event, for later use for crash investigation purposes.
`50
`cord 58, encircling the upper edge of the opening of
`In order to reduce the risk that the passenger will be
`in?ation tube 60, attached to air bag 16, to hold the
`out of proper position, such as being too far forward to
`allow deployment of the air bag, the system has multiple
`in?ation tube 60 in place attached to nozzle 44, and
`prevent in?ation tube 60 from being blown off of nozzle
`means to encourage the passenger to maintain proper
`44 before the bimetallic portion of releasable clamp 48
`position. A warning light 12, on the bottom of mounting
`relaxes to allow release of releasable clamp 48. The
`tunnel 2, will be activated by microprocessor 8, in re
`fabric ?ller cord 58 is a dense, rope-like ?exible material
`sponse to data from passenger sensor array 4, if the
`which, when stitched into place, gives an unyielding
`passenger is not in proper position. But in order to have
`tubular shape to the upper edge of in?ation tube 60. The
`redundancy, and to continuously remind a driver not to
`purpose of the releasable clamp 48 is to automatically
`assume an improper position, a tactile and printed warn
`disengage in?ation tube 60 and air bag 16 from nozzle
`ing sleeve 32 is a?ixed to the steering wheel 28, and
`44 after the crash, to allow de?ation of air bag 16 and
`warns the driver against sitting out of proper position,
`free the passenger from the restraint and blockage of
`such as too far forward, and also to warn against having
`view caused by air bag 16. This is accomplished auto
`the hands on the top portion of steering wheel 28, i.e.
`matically by the effect of heat from burning of the pyro
`from the 10 O’Clock to 20’Clock positions, in which
`65
`technic in?ators 22, carried by the gas exiting in?ation
`the hands might de?ect the deploying air bag so that it
`module 20 through nozzle 44, which heats the releas
`does not position itself betwe