WO1994008819A1

WO1994008819A1 - Air bag device for vehicles

Info

Publication number: WO1994008819A1
Application number: PCT/US1993/010043
Authority: WO
Inventors: Stephen J. Brockman; Michael F. Fink
Original assignee: Ideatech, Inc.
Priority date: 1992-10-21
Filing date: 1993-10-20
Publication date: 1994-04-28
Also published as: AU5445594A

Abstract

An air bag device is made of a reservoir (1) of fluid sealed by a frangible plate (3), and a cushion (2) connected to the reservoir (1). A striking member (29) is mounted so that a conical point is adjacent the plate (3). Lead styphnate (34) and nichrome wire are positioned adjacent the striking member (29). A squib (43) and combustion material (42) are provided to supplement the volume and pressure of the fluid. The squib (43) and the wire are in parallel. If a collision occurs, a signal is sent to the wire to ignite the lead styphnate (34) and drive the conical point of the striking member into the plate (3) to shatter it releasing fluid from the reservoir (1) into the cushion (2). At the same time, the signal ignites the squib (43), which ignites the combustion material (42) which in turn generates products to supplement the volume and pressure of the fluid.

Description

AIR BAG DEVICE FOR VEHICLES

TECHNICAL FIELD This invention relates, broadly speaking, to a safety device for vehicles. More particularly, this invention relates to an improved air bag device for a vehicle, which device can rapidly be deployed in the event of a collision to prevent or reduce the extent of injury to an occupant of the vehicle, which device comprises a collapsed cushion which is inflated by pressurized fluid stored in a reservoir, the said device also comprising fluid-augmenting means to supplement the pressure and volume of the fluid and thereby permit the use of a smaller reservoir and increase the rate of inflation of the cushion.

BACKGROUND ART Air bag devices for vehicles are known. Such air bag devices have, in the past, been based upon the ignition of a quantity of rapidly combustible material, particularly sodium azide, triggered by a collision sensor on the vehicle, to rapidly generate combustion gases in sufficient quantity to inflate the air bag which then acts as a cushion to protect the occupant. of the vehicle from injury which otherwise could result from the occupant coming into violent contact with the steering wheel or dashboard of the vehicle. Although these prior art air bag devices have been instrumental in reducing the number of fatalities or serious injuries, they have a number of shortcomings, among which are the generation of high temperature combustion gases of approximately 300° F which, when vented, have caused serious burns on the body of the occupant, and the problem of disposing of the environment- unfriendly combustible sodium azide in the event, more probable than not, that the vehicle is brought to an automobile junkyard without the air bag device having been deployed as the result of a collision. So dangerous is the sodium azide that government regulations require that it be ignited before automobile junkyards can accept or retain the vehicle.

A notable improvement in air bag devices is disclosed in U.S. Patent No. 5,152,550 (1992), and comprises, among other things: (a) a reservoir containing prior to collision a pressurized fluid and having an outlet,

(b) an inflatable cushion having an inlet and being inflated solely by the pressurized fluid in the reservoir in the event of a collision,

(c) a frangible plate interposed between the outlet of the reservoir and the inlet of the inflatable cushion and preventing the passage of pressurized fluid from the reservoir to the interior of the inflatable cushion, the frangible plate having an upstream side facing the outlet of the reservoir and a downstream side, the frangible plate being brittle and shattering into discrete fragments when struck, (d) a striking member adjacent the downstream side of the frangible plate and having a first end to strike the downstream side of the frangible plate to rapidly shatter the frangible plate, and a second end opposite the first end, and (e) means to rapidly apply a force to the second end of the striking member in response to the signal of a collision, to drive the striking member toward the downstream side of the frangible plate so that the first end of the striking member shatters the frangible plate,

(f) whereupon pressurized fluid escapes from the reservoir and inflates the cushion. Copending U.S. Patent Application Serial No. 07/940,981, filed on September 4, 1992 in the names of Stephen J. Brockman, Michael F. Fink, and Larry D. Hoagland, entitled

"Air Bag Device For Vehicles" and assigned to the assignee of the present application, discloses an air bag device generally similar to that disclosed in U.S. Patent No. 5,152,550, except that the striking member is placed within the reservoir adjacent the upstream or high pressure side of the frangible disc, and means are provided to support the striking member within the reservoir.

Neither U.S. Patent No. 5,152,550 nor U.S. Patent Application Serial No. 07/940,981 discloses the use of combustible materials to augment the pressure of the pressurized fluid, in response to a collision, thereby to accelerate the inflation of the air bag.

U.S. Patent No. 5,076,607 (1991) and U.S. Patent No. 5,022,674 (1991) disclose hybrid air bag inflators wherein pressurized fluid is stored in a reservoir prior to a collision. A quantity of combustible material is placed in a housing within the reservoir, and an opening in the housing leading to the interior of the reservoir is sealed shut by a stainless steel burst disc requiring the application of substantial pressure to rupture and open it. The purpose of the air bag devices disclosed in these patents is to permit the initial flow of unheated pressurized fluid from the reservoir into the air bag. The combustible material in the sealed housing of these patents is ignited in response to a collision and, after an interval of time, pressure in the housing builds up sufficiently to rupture the burst disc, whereupon the products of combustion enter the reservoir proper to heat and thereby augment the pressure of the pressurized fluid. These devices are designed to have a dual flow rate, comprising an initial slow flow rate of cool pressurized fluid into the air bag, followed by a more rapid flow rate of heated pressurized fluid into the air bag. Because pressure in the sealed housing holding the combustible material separate from the reservoir must build up to a level sufficient to burst the disc sealing the housing from the reservoir, before the products of the combustion can enter the reservoir proper, there necessarily will be a time delay in effecting the initiation of the more rapid flow rate. There would appear to be a problem in obtaining reproducibility with an accepted range of bursting pressures required to rupture the seal closing the housing in the structures of these two last mentioned patents. Such problems in obtaining acceptable reproducibility of busting pressure can arise for a number of reasons, among which are variations in thickness of the seal, and of changes in the metallurgy of the seal due to the welding of the seal to the housing. Such variances in bursting pressure necessarily result in variances in the time of initiation of the more rapid flow rate, and would make air bag devices of the type disclosed in these two last mentioned patents less reliable as dual fluid inflators. U.S. Patent No. 3,723,205 (1973) discloses an inflation system for an air bag wherein the pressure and volume of pressurized fluid in a reservoir is augmented by the combustion of a gas generating composition in a combustion chamber closed by a seal and located within the reservoir. The gas generating composition is described as plasticized polyvinyl chloride fuel binder and a mixture of inorganic oxidizing salt and halogen-free alkali metal salt in stoichiometry sufficient at the least to transform all carbon, hydrogen and halogen in the composition to carbon dioxide, water and alkali metal halide. In operation, the gas generating composition is ignited. After a period of time required for the pressure in the sealed combustion chamber to rise sufficiently, the seal ruptures and the hot high pressure products of combustion exit the now-open combustion chamber and enter the reservoir proper, increasing the volume and pressure of the pressurized fluid. A second seal, between the reservoir and the air bag ruptures when the pressure in the reservoir rises sufficiently, and the pressurized contents of the reservoir then pass through the opening previously closed by this second seal and inflate the air bag. The apparatus disclosed in U.S. Patent No. 3,723,205 does not employ a frangible disc adapted to be shattered by a striking member, and requires two time delays before inflation of the air bag is initiated, because of the two seals which must be ruptured seriatim under pressure.

DISCLOSURE OF THE INVENTION One of the objects of this invention is to provide an improved air bag device to protect an occupant of a vehicle from serious injury in the event of a collision.

Other and further objects of this invention will become apparent by reference to the accompanying specification, the drawings and the appended claims.

Briefly, the foregoing advantages are attained by providing a vehicle with a reservoir containing pressurized fluid, a frangible plate interposed between the outlet of the reservoir and the inlet of an inflatable cushion, a striking ember adjacent the frangible plate, the striking member being rapidly advanced in the event of a collision to rapidly shatter the frangible plate, and a small quantity of combustible material which, when ignited in response to a collision, produces a high volume of hot combustion gases which immediately supplements the pressure and volume of the pressurized fluid without first having to rise in pressure substantially to burst a seal as in the prior art. Upon collision, the striking member is driven against the frangible plate to shatter it whereupon pressurized fluid commences to escape from the reservoir to inflate the air bag. At the same time, the combustible material is ignited, generating a high volume of hot combustion gases, which immediately supplements the pressure and volume of the pressurized fluid thereby permitting the use of a smaller reservoir than in the prior art and also increasing the rate of inflation of the air bag.

BRIEF DESCRIPTION OF THE DRAWINGS Referring now to the drawings, in which like numerals represent like parts in the several views: FIGURE 1 represents a medial longitudinal partial section of one embodiment of the present invention, showing diagrammatically the air bag in collapsed (i.e., non-inflated) condition prior to a collision involving the vehicle in which this embodiment of the present invention is mounted. FIGURE 2 represents a partial view in plan of the closure plate as seen from line 2-2 of FIGURE 1.

FIGURE 3 represents a view in plan of the housing for combustible material, taken along the line 3-3 of FIGURE 1. FIGURE 4 represents a section in plan taken along the line of 4 -4 of FIGURE 1.

FIGURE 5 represents a section in elevation taken along the line 5-5 of FIGURE 4, showing the upper end of the actuator cylinder and the upper end of the striking member prior to collision. FIGURE 6 represents an enlarged medial longitudinal partial section of the actuator, showing the striking member slidably mounted therein prior to collision.

FIGURE 7 represents a medial longitudinal partial section of another embodiment of the present invention, showing diagrammatically the air bag in collapsed (i.e., non-inflated) condition prior to a collision involving the vehicle in which this embodiment of the present invention is mounted. FIGURE 8 represents a section in plan taken along the line 8-8 of FIGURE 7.

FIGURE 9 represents a section in elevation taken along the line 9-9 of FIGURE 8, showing the upper end of the actuator cylinder and the upper end of the striking member prior to collision.

FIGURE 10 represents a medial longitudinal partial section of still another embodiment of the present invention, showing diagrammatically the air bag in collapsed (i.e., non-inflated) condition prior to a collision involving the vehicle in which the embodiment of the present invention is mounted.

FIGURE 11 represents an- exploded view, in medial longitudinal section, of the housing with materials ignitable upon collision to generate high-temperature products of combustion, and the actuator mounted therein, for the embodiment of FIGURE 10.

FIGURE 12 represents a medial longitudinal partial section of yet another embodiment of the present invention, showing diagrammatically the air bag in collapsed (i.e., non-inflatable) condition prior to a collision involving the vehicle in which this embodiment of the present invention is mounted.

FIGURE 13 represents a medial longitudinal partial section of a further embodiment of the present invention, showing diagrammatically the air bag in collapsed (i.e., non-inflated) condition prior to a collision involving the vehicle in which this embodiment of the present invention is mounted.

FIGURE 14 represents a medial longitudinal partial section of yet another embodiment of the present invention, showing diagramatically the air bag in collapsed (i.e., non-inflated) condition prior to a collision involving the vehicle in which this embodiment of the present invention is mounted. BEST MODES FOR CARRYING OUT THE INVENTION In the embodiment of FIGURES 1-5, the air bag device is seen as comprising reservoir 1, inflatable air bag or cushion 2, and frangible plate 3 interposed between reservoir 1 and air bag 2.

The inner diameter of reservoir 1 is stepped or reduced as shown so as to provide an inwardly projecting ledge 4 extending completely around the inside of reservoir 1 to support the bottom surface of closure plate 5 during assembly of the air bag device and prior to introducing pressurized fluid therein.

Closure plate 5 is provided with central aperture 6 and radially spaced lips 7 extending partially into central aperture 6. Frangible plate 3 is made of brittle material such as glass and preferably tempered glass, ceramic, porcelain, brittle alloys or mixtures or.composites, brittle sintered material, and is characterized by its tendency to undergo extremely rapid multi-directional crack propagation when struck with sufficient force and thus to rapidly shatter into numerous discrete fragments. In other words, frangible plate 3 virtually instantaneously disintegrates when struck a shattering blow. Plates or discs similar in function to frangible plate 3 are well known in the art of containing pressurized fluid, and are sometimes referred to as "bursting discs." Frangible plate 3 has sufficient strength to withstand the pressure exerted on its bottom or high-pressure force by pressurized fluid in reservoir 1, and does not require any support against such pressure other than the peripheral support of lips 7 on closure plate 5, thus leaving the major central area of frangible plate 3 totally unobstructed.

Closure plate 5 is provided with circumferential recess 8 in which is positioned an elastomeric O-ring seal 9. A cushion gasket 10 is positioned in central aperture 6 around the upper periphery of frangible plate 3.

Frangible plate 3 is supported just below central aperture 6 by means of O-ring seal 9 wedged around the circumferential edge of frangible plate 3. The dimensions of O-ring seal 9 are selected so that the said seal 9 projects sufficiently beyond the recess 8 when in the uncompressed condition to achieve this wedged supporting effect when frangible plate 3 is placed in position in closure plate 5. When pressurized fluid is introduced into reservoir 1, the upper periphery of frangible plate 3 will be forced upwardly against cushion gasket 10 which bears against the bottom surfaces of lips 7.

This supporting arrangement for frangible plate 3, which is held in elastomeric material, protects frangible plate 3 against unintended forces such as mechanical vibrations which otherwise might shatter it and prematurely release pressurized fluid from reservoir 1.

Filter housing 11, provided with radially spaced apertures 12 (only two of which are shown), is bolted to the upper surface of closure plate 5, coaxially with central aperture 6 as shown, by means of radially spaced bolts 13 (only one of which is shown). Filter 14 is positioned within filter housing 11, extending around the inner periphery thereof and thus being interposed between all apertures 12 and the interior of filter housing 11. Filter 14 is preferably a screen mesh of suitable material, and is provided to prevent the numerous discrete fragments resulting from the shattering of frangible plate 3 from entering air bag 2. Recess 15 extends completely around the circumference of closure plate 5 and receives O-ring seal 16 which bears against the inside of reservoir 1.

Recess 17 extends completely around the inside of reservoir 1 and receives split retaining ring 18 which holds closure plate 5 in position in reservoir 1 against ledge 4. Retaining ring 19 extends completely around the peripheral edge of air bag 2 as shown, and is pressed against the said peripheral edge to force the peripheral edge into fluid-tight contact with the top of reservoir 1 by means of radially spaced bolts 20 (only two of which are shown) passing through the retaining ring 19 and peripheral edge of the air bag and tightly threaded into threaded apertures 21 in reservoir 1. Other means for fluid-tightly coupling the air bag 2 to reservoir 1 to prevent leakage of pressurized fluid therebetween will be apparent to those familiar with this art.

Closure plate 5 is formed with bridge 22 spanning central aperture 6 in a different horizontal plane as shown. The width of bridge 22 is just sufficient to have formed therethrough central aperture 23 which receives actuator 24, but is not so wide as to significantly vertically obstruct central aperture 6 in closure plate 5. It will be apparent from the drawings that the vertically unobstructed portion of central aperture 6 in closure plate 5 is, from the fluid-flow functional standpoint, virtually the same as the major central area of frangible plate 3. For ease of assembly, bridge 22 may be a separate piece, and secured to closure plate 5 by means of threaded bolts 22a as shown. As shown in detail in FIGURE 6, actuator 24 consists of cylinder 25 of sufficient thickness and strength as to resist internal collapse or distortion due to the pressure of pressurized fluid in reservoir 1. The bottom end of cylinder 25, which is that end remote from frangible plate 3, is sealed shut by closure means, for example by plate 26 which may be formed integrally with cylinder 25 or which may be a separate piece suitably secured to the bottom end of cylinder 25. The upper end of cylinder 25, which is that end proximate to frangible plate 3, is secured in central aperture 23 of bridge 22 by suitable means known to those familiar with this art, such as threading or cementing. Aperture 23 thus functions as a receptacle for cylinder 25. Guide means, preferably plate 27 having a central orifice 28 extending therethrough, is secured, by suitable means such as threading, cementing, soldering or brazing, in the upper end of cylinder 25. Alternatively, bridge 22 may be formed with an integral orifice functioning as a guide means, above aperture 23. In any event, orifice 28 is coaxial with the longitudinal axis of cylinder 25. Striking member 29 in cylinder 25 has a diameter slidably fitting within orifice 28. The front or upper end of striking member 29, that end used to shatter frangible plate 3, is conically shaped to bring it to a point. Preferably, the conical tip of striking member 29 is made of hardened steel having a Rockwell C hardness of 50-52. The rear or botto end of striking member 29 is provided with piston 30 slidably engaging the inner periphery of cylinder 25. Piston 30 may be formed integrally with striking member 29, or may be secured to striking member 29 in a manner known to those familiar with this art. Vertically spaced from piston 30, along the longitudinal axis of striking member 29, is a second piston 31 formed integrally with or otherwise suitably secured to striking member 29. The diameter of striking member 29 is reduced at 32, and an O-ring seal 33 is maintained in position around section 32 of striking member 29, between pistons 30 and 31.

It will be seen that, in the event of a collision, striking member 29 is guided along its longitudinal axis in travelling to shattering engagement with frangible plate 3 by means of piston 30 sliding in cylinder 25 and striking member 29 sliding in orifice 28. It will be apparent that the conical end of striking member 29, prior to actuation, is positioned in close proximity to, but not in contact with, the high pressure face of frangible plate 3, and that the length of guided engagement of striking member 29 in cylinder is greater than the distance striking member 29 must travel to shatter frangible plate 3 in the event of a collision.

Between the piston 30 and plate 26 is placed a small portion of explosive 34,. preferably lead styphnate and typically no more than 10 milligrams (compared to the 100 - 200 grams of sodium azide conventionally employed to inflate air bags.) Electrical ignition means 35, preferably a length of nichrome wire, is positioned between piston 30 and plate 26 and is covered by explosive 34. A pair of electrical leads 36, connected at one end thereof to the ends of the ignition means 35, passes through hermetically sealed aperture 37 in plate 26 for connection at the other end in a manner to be described further on.

Positioned within reservoir 1 is fluid-augmenting means 38 which is seen as comprising housing 39 provided with numerous apertures 40 and containing a quantity of rapidly combusting hot gas-generating material 41, a quantity of ignition-enhancing material 42 and a squib 43.

Between hot gas-generating material 41 and ignition- enhancing material 42 is disposed metallic screen 44 to diffuse and thereby spread out more uniformly the flame produced by the said ignition-enhancing material 42. This diffusion of the flame produced by the ignition-enhancing material 42 eliminates hot spots and provides for a more uniform and rapid combustion of hot gas-generating material 41

Between squib 43 and ignition-enhancing material 42 is disposed metallic screen 45 to diffuse and thereby spread out more uniformly the flame produced by the said squib 43. This diffusion of the flame produced by the squib 43 eliminates hot spots and provides for a more uniform and rapid combustion of ignition-enhancing material 42.

The purpose of housing 39 is not to retard to any significant degree the passage of the hot products of combustion of the hot gas-generating material 41 from the interior of the said housing 39 into the reservoir 1 proper, but rather is to hold together in proper relation the assembly of the several components therein. Consequently, housing 39 is provided with sufficient apertures 40 around its entire periphery to achieve this end. Thus, when ignition of the materials within housing 39 commences in response to a collision, the pressure-augmenting hot products of combustion of the said materials do not first have to rise to a level sufficient to burst a seal, as in prior art devices, but instead are promptly available to immediately augment the pressure of the pressurized fluid within reservoir 1. Alternatively, housing 39 may be a cage of suitable screen material and of mesh sufficiently large to permit the prompt and substantially unrestricted flow of such products of combustion into reservoir 1.

Housing 39 is secured to reservoir 1 by means of bolts 46 threaded into apertures in the said reservoir 1.

Hot gas-generating material 41, which is a composition that may follow any of the recipes disclosed therefor in U.S. Patent No. 3,723,205 and which may, for example, be the hot gas generator sold under the trademark ARCITE, is capable of producing, when ignited, large volumes of hot products of combustion.

Hot gas-generating material 41 is formed as a cylinder, preferably with a number of passages 47 extending therethrough by means of which the burn rate may be kept within a certain desired range.

Ignition enhancing material 42 is well-known and may, for example, be primarily boron potassium nitrate. To facilitate handling of this material 42, it may be held in a thin metal foil which is scored to facilitate opening and which therefore requires virtually no pressure buildup prior to opening. Squib 43 is well-known as a combustion initiator, and contains material 48 which is ignitable. Squib 43 is positioned in aperture 49 of reservoir 1, and flange 50 in squib 43 prevents squib 43 from being expelled through aperture 49 because of fluid pressure in reservoir 1. O-ring seal 51 is interposed between the periphery of squib 43 and aperture 49, being seated in a recess extending circumferentially either around squib 43 or aperture 49.

Electrical ignition means 52, preferably a length of nichrome wire, is positioned in squib 43, covered by material 48, and the ends thereof are connected to one end of a pair of electrical leads 53.

The pair of electrical leads 36, connected at one end to electrical ignition means 35 in actuator 24 as previously described, passes through apertures in housing 39, hot gas-generating material 41, screen 44, ignition-enhancing material 42, screen 45 and into squib 43, and is connected at the other end to the ends of electrical ignition means 52 or to the pair of electrical leads 53.

Thus, it will be seen that electrical ignition means 35 and electrical ignition means 52 are wired in parallel.

The pair of electrical leads 53, connected at one end to electrical ignition means 52 and, also, in parallel to electrical ignition means 35 as previously described, passes through a hermetically sealed aperture 54 in the bottom of squib 43 and said pair of electrical leads 53 is connected at the other end thereof to one or more collision-sensing means (not shown) on the vehicle in which the air bag device is mounted. Such collision-sensing means are well-known and may, for example, be electrical contact switches or motion detectors such as inertial switches and accelerometerε. These collision-sensing means close an electrical circuit upon the occurrence of a collision involving the vehicle, and thus send an electrical signal to the air bag device. This electrical signal, passing through the pair of electrical leads 53 and the pair of electrical leads 36, and thus through electrical ignition means 52 and 35, will simultaneously ignite the lead styphnate in actuator 24 and the material 48 in squib 43. Ignition of the lead styphnate in actuator 24 will rapidly generate combustion gases which act against piston 30 thus driving striking member 29 along its longitudinal axis into frangible plate 3 so as to rapidly shatter the same and virtually instantaneously permit the passage of pressurized fluid from reservoir 1 through aperture 6 in closure plate 5 and thence into air bag 2.

Virtually simultaneously with the ignition of the lead styphnate in actuator 24, ignition of the material 48 in squib 43 ignites ignition-enhancing material 42 and thus ignites hot gas- generating material 41 in fluid-augmenting means 38, producing a high volume of hot products of combustion which immediately enter the reservoir 1 through apertures- 40 in housing 39, and thus immediately elevating the temperature and pressure of, and supplementing the volume of, pressurized fluid passing from reservoir 1 through aperture 6 in closure plate 5. The rate of discharge of pressurized fluid from reservoir 1 is accelerated, and therefore the rate of inflation of air bag 2 is likewise accelerated.

The major central area of frangible plate 3 which is shattered and disintegrated when struck by striking member 29, the area of aperture 6 in closure plate 5, and the combined areas of apertures 12 in filter housing 11 each must be sufficiently large to permit the rapid passage of pressurized fluid from reservoir 1 into air bag 2.

The shattering effect of striking member 29 on frangible plate 3 permits the virtually instantaneous escape of pressurized fluid from reservoir 1, thence 'through central aperture 6 in closure plate 5, thence through filter 14, thence through apertures 12 in filter housing 11, and finally into air bag 2 to deploy the said air bag 2 by inflating it. It will be apparent that the pair of electrical leads 36 must be connected to the ends of electrical ignition means 52 or to the pair of electrical leads 53 in such manner as to place electrical ignition means 35 in parallel with electrical ignition means 52, before closure plate 5 is secured in position at the upper end of reservoir 1. For this reason, it may be desirable to employ electrical leads 36 of sufficient length to provide adequate slack. It may also be desirable to interpose in electrical leads 36, between actuator 24 and pressure-augmenting means 38, a pair of mating male/female connectors or plugs (not shown) of known design.

Reservoir 1 is filled with pressurized fluid through conduit 55 tightly threaded at one end into threaded aperture 56 extending through the wall of reservoir 1. The other end of conduit 55 is adapted to be connected to a source of pressurized fluid, and is provided with shut-off valve 57 to permit the conduit 55 to be disconnected from the source of pressurized fluid while retaining pressure within reservoir 1. A pressure gauge 58 may be provided in conduit 55 to permit verification of the amount of pressure within reservoir 1.

In the embodiment of FIGURES 7-9, which is generally similar to the embodiment of FIGURES 1-5, closure plate 5 is modified to include legs^' 59 across which extends bridge 22. For ease of assembly, bridge 22 may be a separate piece, secured to legs 59 by means of threaded bolts 60 as shown. Bridge 22 is thus maintained in a plane sufficiently below frangible plate 3 as to permit the bottom end of cylinder 25 of actuator 24, sealed shut by plate 26 secured thereto, to be secured in aperture 23 of bridge 22, aperture 23 functioning as a receptacle for cylinder 25, and to permit the conical end of striking member 29 to be positioned relative to the bottom or high-pressure face of frangible plate 3 the same distance as in the embodiment of FIGURES 1-5. The manner of securement of the bottom end of cylinder

25 in aperture 23 will be the same as previously described for securing the upper end of cylinder 25 into the said aperture 23 for the embodiment of FIGURES 1-5. In assembling actuator 24, plate 27 with orifice 28 therethrough coaxially positioned relative to the longitudinal axis of cylinder 25 and slidably receiving striking member 29, will be secured in the upper end of cylinder 25 in a suitable manner as by threading or cementing. As with the embodiment of FIGURES 1-55, electrical leads 36 pass through a hermetically sealed aperture in plate 37.

The assembly and operation of the embodiment of FIGURES 7-9 is similar to the assembly and operation of the embodiment of FIGURES 1-5. In the embodiment of FIGURES 10-11, closure plate 5 does not have the bridge 22 of the previously disclosed embodiments. Instead, actuator 24 is supported from the bottom of reservoir 1 in a manner to be described.

Closure plate 5 is provided with circumferential recess 61 receiving O-ring seal 62 which holds frangible plate 3 in position.

Fluid-augmenting means 38, mounted within reservoir 1, comprises housing 39 with numerous apertures 40 and containing hot gas-generating material 41, ignition-enhancing material 42, diffusing screen 44 interposed therebetween, squib 43, and diffusing screen 45 on top of squib 43, all as hereinbefore described.

Aperture 63 is provided in the bottom of reservoir 1 and does not extend all the way through the bottom wall thereof, thereby provided a shelf upon which seats squib 43. There is therefore, no need for a flange 50 on said squib 43 as in the previously described embodiments. An O-ring seal 43a extends around squib 43 as shown.

Squib 43 is provided with recess 64 of size and shape adapted to receive the lower portion of cylinder 25 of actuator 24. A pair of female plugs 65 is provided at the bottom of recess 64 and electrical ignition means 52 (preferably a length of nichrome wire) is connected across said female plugs 65 as shown. The electrical ignition means 36 (the length of nichrome wire) in cylinder 25 of actuator 24 is connected to one end of a pair of electrical leads 67 which extends through hermetically sealed apertures in plate 26 at the bottom of cylinder 25. The other end of the pair of electrical leads 67 is connected to a pair of male plugs 68.

Male plugs 68 mate with female plugs 65, when cylinder 25 of actuator 24 is fully seated in recess 64 of squib 43, and thus electrical ignition means 36 and electrical ignition means 52 will be wired in parallel.

Suitable apertures 69 are provided through housing 39, diffusing screen 44, ignition-enhancing material 42 and diffusing screen 45, to permit actuator 24 to extend therethrough.

The distance between the conical end of striking member 29 and the bottom or high-pressure face of frangible plate 3, when actuator 24 is fully seated in recess 64 of squib 43, is the same as in the previously described embodiments. This arrangement permits a very shallow reservoir 1 to be employed, which may be useful in meeting certain physical constraints on placement in the vehicle.

The pair of electrical leads 70 is connected at one end to female plugs 65 as shown, and extends through a hermetically sealed aperture in the bottom wall of reservoir 1. The other end of the pair of electrical leads 70 is connected to collision-sensing means as in the previously described embodiments.

The assembly and operation of the embodiment of FIGURES 10-11 is similar to the assembly and operation of the previously described embodiments.

In the embodiment of FIGURE 12, filter housing 11 is provided with internal boss 71 having counterbore 72 receiving that end of actuator 24 remote from the conical tip of striking member 29. A pair of electrical leads 36, connected at one end to electrical ignition means 35 in actuator 24 extends across the top of filter housing 11, below air bag 2, and through aperture 73 in the upper side wall of reservoir 1. The other end of the pair of electrical leads 36 is connected in parallel to the pair of electrical leads 53, which is connected at one end to electrical ignition means 52 in squib 43 of fluid-augmenting means 38 in reservoir 1. Therefore, electrical ignition means 35 in actuator 24 and electrical ignition means 52 in squib 43 are wired in parallel. The other end of the pair of electrical leads 53 is connected to collision sensing means as in the previously disclosed embodiments.

The depth of filter housing 11 in the embodiment of FIGURE 12 is increased over that of the filter housings 11 of the previously disclosed embodiments, so that the distance between the conical tip of striking member 29 and the upper or low pressure side of frangible plate 3 is the same as the distance between said conical tip and the bottom or high-pressure side of frangible plate 3 in the previously described embodiments.

As in the embodiment of FIGURE 10-11, in the embodiment of FIGURE 12, closure plate 5 is provided with circumferential recess 61 receiving O-ring seal 62 which holds frangible plate 3 in position.

The assembly and operation of the embodiment of FIGURE 12 is similar to the assembly and operation of the previously disclosed embodiments.

In the embodiment of FIGURE 13, fluid-augmenting means 38 is positioned in the filter housing 11, annularly disposed about actuator 24 as shown.

In particular, the specific arrangement of fluid-augmenting means 38 and actuator 24 with all components shown in FIGURE 10 is used, but instead is positioned upside down in filter housing 11. In this arrangement, the pressure and volume of pressurized fluid exiting reservoir 1 in the event of a collision are augmented by hot combustion gases within filter housing 11.

JS.299

Claims

We cl a im :

1. For use in a vehicle having collision-sensing means mounted thereon to rapidly generate a signal in response to a collision, cushioning apparatus to be mounted in said vehicle and deployed upon collision to protect an occupant in said vehicle from injury, said cushioning apparatus comprising: a reservoir containing prior to collision a pressurized fluid and having an outlet, an inflatable cushion having an inlet, said inflatable cushion being inflated in part by pressurized fluid from said reservoir in the event of a collision, a frangible plate interposed between the outlet of said reservoir and the inlet of said inflatable cushion and preventing the passage of pressurized fluid from said reservoir to said inflatable cushion, said frangible plate having an upstream side facing the outlet of said reservoir and a downstream side opposite said upstream side,' said frangible plate rapidly shattering into discrete fragments when struck, first means to support said frangible plate around the periphery thereof so as to leave the major central area of said frangible plate unobstructed, a striking member adjacent one side of said frangible plate and having a longitudinal axis, a first end to strike said frangible plate and rapidly shatter said frangible plate, a second end opposite said first end, and a transverse cross-section substantially smaller than the major central area of said frangible plate, second means mounting said striking member for movement along said longitudinal axis toward said frangible plate, third means to rapidly apply a force to the second end of said striking member in response to a signal generated by said collision-sensing means to drive said striking member along said longitudinal axis toward said frangible plate so that the first end of said striking member shatters said frangible plate, whereby to provide a passage adjacent said striking member of area adequate to permit the rapid flow therethrough of said pressurized fluid from said reservoir into said inflatable cushion in response to a signal generated by said collision-sensing means to inflate said cushion, and filter means interposed between the downstream side of said frangible plate and the inlet of said inflatable cushion, said cushioning means being characterized in that: (a) fluid-augmenting means are provided and are ignitable in response to the signal generated by said collision-sensing means to generate hot products of combustion which immediately upon ignition commence to supplement the pressure and volume of said fluid before said fluid enters said inflatable cushion.

2. Apparatus as in claim 1, further characterized in that said fluid-augmenting means is mounted within said reservoir.

3. Apparatus as in claim 1, further characterized in that said fluid-augmenting means is interposed between said filter means and the downstream side of said frangible plate.

4. Apparatus as in claim 1, further characterized in that said striking member, said third means, and said fluid-augmenting means are mounted within said reservoir.

5. Apparatus as in claim 1, further characterized in that:

(b) said striking member and said third means are mounted within said reservoir,

(c) said fluid-augmenting means is interposed between said filter means and the downstream side of said frangible plate.

6. Apparatus as in claim 1, further characterized in that:

(b) an apertured housing is secured to said apparatus adjacent the downstream side of said frangible plate and upstream of the inlet of the inflatable cushion,

(c) said filter means is positioned in said housing between the apertures therein and the downstream side of said frangible plate,

(d) said fluid-augmenting means is positioned in said housing between said filter means and the downstream side of said frangible plate. 7. Apparatus as in claim 1 wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(b) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into said frangible plate, (c) second electrical ignition means is operatively connected to said fluid-augmenting means to ignite said fluid-augmenting means in response to the electrical signal generated by said collision-sensing means indicating a collision, (d) said first and second electrical ignition means are wired in parallel. 8. Apparatus as in claim 1, further characterized in that said fluid-augmenting means comprises:

(b) a squib which is ignited upon communication of a signal from said collision-sensing means indicating a collision,

(c) a quantity of combustible material which is ignited by the squib when the collision-sensing means generates a signal indicating a collision and which generates upon ignition a substantial volume of hot products of combustion,

(d) a housing with apertures therethrough and containing said quantity of combustible material, said apertures permitting unrestricted access at all times by said hot products of combustion to said pressurized fluid. 9. Apparatus as in claim 8, further characterized in that:

(e) said striking member is positioned within said reservoir with the first end thereof adjacent the upstream side of said frangible plate,

(f) said third means is positioned within said reservoir,

(g) said fluid-augmenting means is positioned within said reservoir, (h) an aperture extends through said fluid-augmenting means, (i) first wiring means is connected at one end to said first electrical ignition means and extends through said aperture in said fluid-augmenting means, the other end of said first wiring means being connected to said second electrical ignition means, (j) second wiring means is connected at one end to said second electrical ignition means and extends through the wall of said reservoir, the other end of said second wiring means being connected to said collision-sensing means. 10. Apparatus as in claim 1, further characterized in that: (b) said fluid-augmenting means is mounted within said reservoir to that wall of said reservoir opposite said frangible plate and is provided with a passageway extending therethrough,

(c) said striking member is positioned in said passageway within said fluid-augmenting means, the first end of said striking member being adjacent the upstream side of said frangible plate,

(d) said third means is positioned within said passageway in said fluid-augmenting means. 11. Apparatus as in claim 10, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(e) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into the upstream side of said frangible plate, (f) second electrical ignition means is operatively connected to said fluid-augmenting means to ignite said fluid-augmenting means in response to the electrical signal generated by said collision-sensing means indicating a collision, (g) said first and second electrical ignition means being wired in parallel. 12. Apparatus as in claim 10, further characterized in that said fluid-augmenting means comprises:

(e) a squib which is ignited upon communication of a signal from said collision-sensing means indicating a collision,

(f) a quantity of combustible material which is ignited by the squib when the collision-sensing means generates a signal indicating a collision and which generates a substantial volume of hot products of combustion,

(g) a housing with apertures therethrough and containing said quantity of combustible material, said apertures permitting unrestricted access at all times by said hot products of combustion to said pressurized fluid.

13. Apparatus as in claim 1, further characterized in that: (b) said striking member is interposed between said filter means and the downstream side of said frangible plate, (c) said third means is positioned downstream of said frangible plate, (d) said fluid-augmenting means is mounted within said reservoir.

14. Apparatus as in claim 13, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that: (e) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into the downstream side of said frangible plate,

(f) second electrical ignition means is operatively connected to said fluid-augmenting means to ignite said fluid augmenting means in response to the electrical signal generated by said collision-sensing means indicatihg a collision,

(g) said first and second electrical ignition means being wired in parallel.

15. Apparatus as in claim 1, further characterized in that :

(b) said fluid-augmenting means is interposed between said filter means and the downstream side of said frangible plate, (c) said striking member is interposed between said filter means and the downstream side of said frangible plate,

(d) said third means is positioned downstream of said frangible plate. 16. Apparatus as in claim 15, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(e) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into the downstream side of said frangible plate, (f) second electrical ignition means is operatively connected to said fluid-augmenting means to ignite said fluid-augmenting means in response to the electrical signal generated by said collision-sensing means indicating a collision, (g) said first and second electrical ignition means being wired in parallel. 17. Apparatus as in claim 1, further characterized in that:

(c) said filter means is positioned in said housing between the apertures thereof and the downstream side of said frangible plate, (d) said fluid-augmenting means is positioned in said housing between said filter means and the downstream side of said frangible plate and is provided with a passageway extending therethrough, (e) said striking member is positioned in said passageway within said fluid-augmenting means, the first end of said striking member being adjacent the downstream side of said frangible plate,

(f) said third means is positioned within said passageway in said fluid-augmenting means.

18. Apparatus as in claim 17, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(g) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into the downstream side of said frangible plate.

(h) second electrical ignition means is operatively connected to said fluid-augmenting means to ignite said fluid-augmenting means in response to the electrical signal generated by said collision-sensing means indicating a collision,

(i) said first and second electrical ignition means being wired in parallel. 19. Apparatus as in claim 1, further characterized in that: (b) an apertured first housing is secured to said apparatus adjacent the downstream side of said frangible plate and upstream of the inlet of the inflatable cushion,

(c) said filter means is positioned in said first housing between said filter means and the downstream side of said frangible plate,

(d) said fluid-augmenting means is positioned in said first housing between said filter means and the downstream side of said frangible plate, said fluid-augmenting means comprising:

(i) a squib which is ignited upon communication of a signal from said collision-sensing means, (ii) a quantity of combustible material which is ignited by the squib when the collision-sensing means generates a signal indicating a collision and which generates a substantial volume of hot products of combustion, (iii) a second housing with apertures therethrough and containing said quantity of combustible material, the apertures in said second housing permitting unreεtructured access at all times by said hot products of combustion to said pressurized fluid. 20. Apparatus as in claim 19, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(e) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into the downstream side of said frangible plate, (f) second electrical ignition means is operatively connected to said squib to ignite said squib in response to the electrical signal generated by said collision-sensing means indicating a collision, (g) said first and second electrical ignition means being wired in parallel.

21. Apparatus as in claim 19, further characterized in that:

(e) said fluid-augmenting means is provided with a passageway extending therethrough, (f) said striking member being positioned in said passageway within said fluid-augmenting means, (g) said third means being positioned within said passageway in said fluid-augmenting means. AMENDED CLAIMS

[received by the International Bureau on 5 January 94 (05.01.94); original claims 1, 5, 9 and 10 amended; remaining claims unchanged (8 pages)]

1. For use in a vehicle having collision-sensing means mounted thereon to rapidly generate a signal in response to a collision, a cushioning apparatus to be mounted in said vehicle and deployed upon collision to protect an occupant in said vehicle from injury, said cushioning apparatus comprising: a reservoir containing prior to collision a pressurized fluid and having an outlet, an inflatable cushion having an inlet, said inflatable cushion being inflated in part by pressurized fluid from said reservoir in the event of a collision, a frangible plate interposed between the outlet of said reservoir and the inlet of said inflatable cushion and preventing the passage of pressurized fluid from said reservoir to said inflatable cushion, said frangible plate having an upstream side facing the outlet of said reservoir and a downstream side opposite said upstream side, said frangible plate rapidly shattering into discrete fragments when struck, first means to support said frangible plate around the periphery thereof so as to leave the major central area of said frangible plate unobstructed, a striking member adjacent one side of said frangible plate and having a longitudinal axis, a first end to strike said frangible plate and rapidly shatter said frangible plate, a second end opposite said first end, and a transverse cross-section substantially smaller than the major central area of said frangible plate, second means mounting said striking member for movement along said longitudinal axis toward said frangible plate, third means to rapidly apply a force to the second end of said striking member in response to a signal generated by said collision-sensing means to drive said striking member along said longitudinal axis toward said frangible plate so that the first end of said striking member shatters said frangible plate, whereby to provide a passage adjacent said striking member of area adequate to permit the rapid flow therethrough of said pressurized fluid from said reservoir into said inflatable cushion in response to a signal generated by said collision-sensing means to inflate said cushion, and filter means interposed between the downstream side of said frangible plate and the inlet of said inflatable cushion, said cushioning means being characterized in that: (a) fluid-augmenting means are provided and are ignitable in response to the signal generated by said collision-sensing means to generate hot products of combustion which immediately upon ignition contact and commence to supplement the pressure and volume of said pressurized fluid before said fluid enters said inflatable cushion, said hot products of combustion contacting said pressurized fluid free of retardation.

5. Apparatus as in claim 1, further characterized in that

(b) said striking member and said third means are mounted within said reservoir, and

6. Apparatus as in claim 1, further characterized in that:

(d) said fluid-augmenting means is positioned in said housing between said filter means and the downstream side of said frangible plate.

7. Apparatus as in claim 1 wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that: (b) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into said frangible plate,

(c) second electrical ignition means is operatively connected to said fluid-augmenting means to ignite said fluid-augmenting means in response to the electrical signal generated by said collision-sensing means indicating a collision,

(d) said first and second electrical ignition means are wired in parallel.

8. Apparatus as in claim 1, further characterized in that said fluid-augmenting means comprises:

(d) a housing with apertures therethrough and containing said quantity of combustible material, said apertures permitting unrestricted access at all times by said hot products of combustion to said pressurized fluid.

9. Apparatus as in claim 8, further characterized in that:

(f) said third means is positioned within said reservoir,

(g) said fluid-augmenting means is positioned within said reservoir,

(h) an aperture extends through said fluid-augmenting means, (i) first wiring means is connected at one end to said first electrical ignition means and extends through said aperture in said fluid-augmenting means, the other end of said first wiring means being connected to said second electrical ignition means, (j) second wiring means extends into said reservoir and is connected at one end to said second electrical ignition means, the other end of said second wiring means being connected to said collision-sensing means.

10. Apparatus as in claim 1, further characterized in that:

(b) said fluid-augmenting means is mounted within said reservoir to that portion of said reservoir opposite said frangible plate and is provided with a passageway extending therethrough,

(d) said third means is positioned within said passageway in said fluid-augmenting means.

11. Apparatus as in claim 10, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(e) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into the upstream side of said frangible plate,

(f) second electrical ignition means is operatively connected to said fluid-augmenting means to ignite said fluid-augmenting means in response to the electrical signal generated by said collision-sensing means indicating a collision,

(g) said first and second electrical ignition means being wired in parallel.

12. Apparatus as in claim 10, further characterized in that said fluid-augmenting means comprises:

(g) a housing with apertures therethrough and containing said quantity of combustible material, said apertures permitting unrestricted access at all times by said .hot products of combustion to said pressurized fluid.

13. Apparatus as in claim 1, further characterized in that:

(b) said striking member is interposed between said filter means and the downstream side of said frangible plate,

(c) said third means is positioned downstream of said frangible plate,

(d) said fluid-augmenting means is mounted within said reservoir.

14. Apparatus as in claim 13, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(e) first electrical ignition means is operatively connected to said third means to actuate said third means in response to an electrical signal generated by said collision-sensing means indicating a collision, thereby to drive the first end of said striking member into the downstream side of said frangible plate,

(f) second electrical ignition means is operatively connected to said fluid-augmenting means to ignite said fluid augmenting means in response to the electrical signal generated by said collision-sensing means indicating a collision,

_Wv_l_HDbU Wtr: iA-"^πh (g) said first and second electrical ignition means being wired in parallel.

15. Apparatus as in claim 1, further characterized in that:

(b) said fluid-augmenting means is interposed between said filter means and the downstream side of said frangible plate,

(c) said striking member is interposed between said filter means and the downstream side of said frangible plate,

(d) said third means is positioned downstream of said frangible plate.

16. Apparatus as in claim 15, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(g) said first and second electrical ignition means being wired in parallel.

17. Apparatus as in claim 1, further characterized in that:

(c) said filter means is positioned in said housing between the apertures thereof and the downstream side of said frangible plate,

(d) said fluid-augmenting means is positioned in said housing between said filter means and the downstream

. . ..-. ι..ι ___ -.C side of said frangible plate and is provided with a passageway extending therethrough,

(e) said striking member is positioned in said passageway within said fluid-augmenting means, the first end of said striking member being adjacent the downstream side of said frangible plate,

(i) said first and second electrical ignition means being wired in parallel.

19. Apparatus as in claim 1, further characterized in that:

(b) an apertured first housing is secured to said apparatus adjacent the downstream side of said frangible plate and upstream of the inlet of the inflatable cushion,

(i) a squib which is ignited upon communication of a signal from said collision-sensing means, (ii) a quantity of combustible material which is ignited by the squib when the collision-sensing means generates a signal indicating a collision and which generates a substantial volume of hot products of combustion, (iii) a second housing with apertures therethrough and containing said quantity of combustible material, the apertures in said second housing permitting unrestructured access -at all times by said hot products of combustion to said pressurized fluid.

20. Apparatus as in claim 19, wherein said collision-sensing means generates an electrical signal in response to a collision, further characterized in that:

(f) second electrical ignition means is operatively connected to said squib to ignite said squib in response to the electrical signal generated by said collision-sensing means indicating a collision,

(g) said first and second electrical ignition means being wired in parallel.

21. Apparatus as in claim 19, further characterized in that:

(e) said fluid-augmenting means is provided with a passageway extending therethrough,

(f) said striking member being positioned in said passageway within said fluid-augmenting means,

(g) said third means being positioned within said passageway in said fluid-augmenting means.

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