Patent Description:
The use of inflatable airbags/cushions to protect individuals from impact (e.g., automotive airbags) is known in the art. Applications of this technology to the protection of ambulating individuals, in particular, elderly individuals that are prone to falls, is a more recent development.

Deployment of active protective devices to attenuate impact and fall-related injuries in the elderly presents unique problems, one of which is the need to deploy such devices in such a way not to startle or alarm the wearer or bystanders by loud sounds. Loud sounds attend the rapid release of gas from canisters, pyrotechnics, or other inflating devices. Pressurization of cold gas inflators applicable to some active protective devices can range from <NUM> to <NUM> kPa (<NUM> to <NUM> psi), and the release of this gas must be accomplished within timeframes of often less than <NUM> milliseconds. This can result in creation of very loud sounds, for example, on the order of <NUM> decibels or more. Such sounds are detrimental in devices intended for use in nursing homes, hospitals, managed care facilities, etc., as well as in the home environment. While sound attenuation mechanisms have been disclosed for firearms, automobile exhaust, and other various industrial applications, sound attenuation of inflators for personal airbags/cushions are as yet unknown. To achieve a practical solution to the suppression of loud noises associated with the deployment of personal protective airbags/cushions, certain restrictions that do not apply to sound suppression technology utilized in firearm, automotive, or industrial applications are required, such as size, weight, and conformation to human anatomy.

<CIT> discloses an inflator delivering gases to an inflatable member (<NUM>), such as used in an inflatable seat belt or air bag.

<CIT> discloses an inflatable safety cushion device for protecting vehicle passengers that includes a filter-muffler for removing any potentially harmful particles from air flowing into an inflating bag, and for reducing the noise level of the inflating air flow.

<CIT> discloses an inflatable curtain gas delivery tube that provides energy absorption and a curtain system that uses the gas delivery tube.

<CIT> discloses an air bag assembly comprising: an inflator for providing a source of inflation gas, and an air bag having a first end and a second end and a first side and a second side, the air bag configured to have a first inflatable chamber proximate the first end, a second inflatable chamber proximate the second and a non-inflatable region therebetween.

One object of certain embodiments of the present invention is to address the above-mentioned problems by providing a noise suppression device that can suppress or attenuate the noise caused by typical inflating devices used in personal impact protection systems. Another object of certain embodiments of the present invention is to provide such a device in a form that is adaptable for use in flexible garments to be worn by an individual for whom personal protection is desired.

The present disclosure describes practical devices for suppressing the loud sounds associated with discharges of gas from chemical, pyrotechnic, or stored gas inflation sources, and in particular, the sufficient suppression of such sounds for a personal protective airbag/cushion. In certain embodiments of the present invention, this object is achieved by a combination of gas restriction, dissipation, baffling, and expansion containment, alone or in combination, and with a configuration of light weight and low bulk, conformable to human anatomy.

According to the present invention there is provided a system as defined in claim <NUM>.

The foregoing summary, as well as the following detailed description of illustrative embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. It should be understood, however, that the application is not limited to the precise arrangements and configurations shown.

Referring to <FIG>, an illustrative inflator and noise suppression assembly is depicted, in which an inflator <NUM> with at least one inflator discharge port <NUM> is affixed to housing <NUM>. The inflator may be, for example, a compressed gas canister, or may be a high pressure gas source with a solid or liquid material that is catalytically or pyrotechnically made to undergo a reaction, such as oxidation, that releases an amount of gas sufficient to develop a predetermined pressure. Inflation may also be achieved through a combination of chemical reaction as well as compressed gas contained in the same housing. Housing <NUM> is comprised of a material sufficient to withstand pressure of contained gas and release of that gas or reaction of inflation chemicals. This material may be, for example, steel, aluminum, an engineered polymer, or a composite material such as carbon fiber. Housing <NUM> is securely affixed to a flexible permeable inner tube <NUM> which, upon inflator activation as necessary to inflate a personal airbag/cushion, serves to provide a first chamber for inflator discharge gas to exit from housing discharge port <NUM> and at least partially expand along the length of permeable inner tube <NUM>, thereby at least partially dissipating the impulse of inflator discharge gas. The permeable inner tube <NUM> is composed of a woven polyester, nylon, Kevlar or metallic fiber, such that the density of fibers within its woven structure create a porosity sufficient to allow inflator discharge gas to permeate through its wall, thereby further dissipating the impulse of inflator discharge gas. Further, permeable inner tube <NUM> may take on an initial shortened, folded configuration such that discharge of inflator gas unfolds and lengthens permeable inner tube <NUM> to further dissipate the impulse of inflator discharge gas. Surrounding permeable inner tube <NUM> is a flexible outer tube <NUM>, which forms a second chamber for inflator discharge gas to exit from permeable inner tube <NUM> and expand along the length of outer tube <NUM>, thereby further dissipating the impulse of inflator discharge gas. The outer tube <NUM> is composed of a woven polyester, nylon or Kevlar with or without an impermeable inner coating composed materials such as polyurethane, natural rubber, silicone and others. The outer tube <NUM> contains one or more outer tube discharge ports <NUM>. Optionally, interspersed between permeable inner tube <NUM> and outer tube <NUM> may be a sound absorption layer <NUM>, which may be comprised of any number of materials such as fiberglass, aerogel, felt, an aramid fiber such as Kevlar, another aramid material such as Nomex, open-cell foam, polybenzobisoxazole, and the like, alone or in combination, to further dissipate energy produced by inflator discharge gas exiting from permeable inner tube <NUM> prior to exiting from the at least one outer tube discharge port <NUM> to inflate a personal airbag/cushion. Sound absorption layer <NUM> may alternatively be comprised of at least one tubular layer of a strong permeable woven fabric to impart a similar effect as permeable inner tube <NUM> to dissipate and decelerate inflator discharge gas.

Referring to <FIG>, another illustrative inflator and noise suppression assembly is depicted, in which an inflator <NUM> with at least one inflator discharge port <NUM> is affixed to housing <NUM>. Housing <NUM> is securely affixed to non-permeable tube <NUM> which, upon inflator activation as necessary to inflate a personal airbag/cushion, serves to provide a chamber for inflator discharge gas to exit from housing discharge port <NUM> and expand along the length of tube <NUM>, thereby at least partially dissipating the impulse of inflator discharge gas. Tube <NUM> further contains along its length, or is adjacent to, at least one permeable gas diffuser element <NUM> to further dissipate the impulse of the inflator discharge gas, in a manner such that discharge gas enters restrictor element <NUM> via inlet port <NUM>, travels through diffuser element <NUM>, and exits via outlet port <NUM>, prior to releasing into a personal airbag/cushion via tube discharge port <NUM>. Optionally, an additional length of the non-permeable tube <NUM> may be provided between the gas diffuser element <NUM> and the discharge port <NUM>. Optionally, the additional length of non-permeable tube <NUM> and the discharge port may be omitted, so that gas enters the personal airbag/cushion directly from the gas diffuser element. Permeable gas diffuser element <NUM> may be made of, for example, porous metal foam, tightly woven metal or non-metal screens, and the like. Alternatively, permeable gas diffuser element <NUM> may be a composite structure comprised of an outer permeable enclosure housing a number of smaller restrictive elements, such as polymeric foam beads, elastomeric beads, sand, vermiculite beads, and glass beads to provide a suitable noise attenuating medium within the enclosure.

Referring to <FIG>, another illustrative inflator and noise suppression assembly is depicted, in which an inflator <NUM> with at least one inflator discharge port <NUM> is affixed to housing <NUM>. Housing <NUM> incorporates a radial extension <NUM> communicating with housing discharge port <NUM> which, upon inflator activation as necessary to inflate a personal airbag/cushion, serves to channel inflator discharge gas through permeable gas diffuser plug <NUM> and out radial exchange discharge port <NUM>, thereby dissipating and decelerating the impulse of inflator discharge gas prior to it releasing into a personal airbag/cushion. Permeable gas diffuser plug <NUM> may be made of, for example, similar materials as aforementioned for permeable gas diffuser element <NUM>.

Referring to <FIG>, another illustrative inflator and noise suppression assembly is depicted, in which an inflator <NUM> with at least one inflator discharge port <NUM> is affixed to housing <NUM>. Housing <NUM> is securely affixed to a sacrificial inner tube <NUM> made of a non-permeable or slightly permeable material, and sealed to create a pressure vessel. Sacrificial inner tube <NUM> further provides, upon inflator activation as necessary to inflate a personal airbag/cushion, a chamber for inflator discharge gas to exit from housing discharge port <NUM> and expand along the length of sacrificial inner tube <NUM>, thereby at least partially dissipating the impulse of inflator discharge gas. Surrounding and in close contact with sacrificial inner tube <NUM> is outer tube <NUM>, which has radial and hoop strength stronger than that of sacrificial inner tube <NUM>, and which further has at least one outer tube discharge port <NUM> positioned at its end or along its length. The outer tube <NUM> may be composed of a woven polyester, nylon, kevlar, or other textile with or without an impermeable inner coating composed materials such as polyurethane, natural rubber, butyl rubber, silicone, and others. The sacrificial inner tube <NUM> may be a lighter weight woven textile of similar composition to the outer layer, or it may be an elastomer such as polyurethane, natural rubber, butyl rubber, silicone, and others without any textile reinforcement. Bursting pressure of the outer tube <NUM> will be significantly greater than that of the sacrificial inner tube <NUM>. An example of bursting pressure relationship is an outer tube <NUM> with a bursting pressure of 8273kPa (<NUM> psi) and a sacrificial inner tube <NUM> with a bursting pressure of 1378kPa (<NUM> psi) Exact bursting pressure ratio may be less or significantly more than this. Each of the at least one outer tube discharge ports <NUM> creates a weak point <NUM> in the overlying wall of sacrificial inner tube <NUM>, such that upon reaching sufficient pressurization of sacrificial inner tube <NUM>, each of the at least one weak points <NUM> will rupture, thereby releasing inflator discharge gas through the at least one outer tube discharge port <NUM>, thereby further dissipating and decelerating the impulse of inflator discharge gas prior to it releasing into a personal airbag/cushion.

Referring to <FIG>, an inflator <NUM> incorporating noise suppression means is depicted, whereby a plurality of inflator discharge ports can be configured in such a manner that at least one larger inflator discharge port <NUM> can be oriented within an array of smaller inflator discharge ports <NUM>. The number, diameters, orientation, and positioning of discharge ports <NUM> and <NUM> can be designed to produce a defined overall acoustic frequency which would be effectively attenuated by a device employed downstream of the discharge ports <NUM> and <NUM>.

Referring to <FIG>, a cold gas inflator <NUM> incorporating an internal noise suppression mechanism is depicted, whereby upon triggering opening of burst disc <NUM> as necessary to inflate a personal airbag/cushion, inflator discharge gas is released through internal orifice <NUM>, travels across internal baffling elements <NUM>, which dissipate and decelerate the impulse of inflator discharge gas and also reduce noise through the principle of resonant absorption, prior to exiting the inflator <NUM> through the at least one inflator discharge port <NUM>. It should be appreciated by those skilled in the art that internal baffling elements <NUM> can be replaced with or used in combination with other devices and materials for noise attenuation, such as a porous metal foam diffuser.

Referring now to <FIG>, another illustrative inflator and noise suppression assembly is depicted, in which an inflator <NUM> with at least one inflator discharge port <NUM> is affixed to housing <NUM>. Housing <NUM> is securely affixed to a flexible, non-permeable segmented tube <NUM> comprising a plurality of sequential chambers <NUM>, with each sequential chamber <NUM> communicably linked to one another via burst seam <NUM>. Burst seam <NUM> may be sealed to provide a sacrificial barrier between sequential chambers <NUM>, may be partially open to restrict air flow between sequential chambers <NUM>, or may be configured in a combination of both types along the length of segmented tube <NUM>.

In an embodiment employing partially open burst seams <NUM>, each sequential chamber <NUM> provides a defined volume for at least partial expansion of inflator discharge gas, which is sequentially stepped down in pressure upon gas passing through each sequential chamber <NUM> and busting each partially open burst seam <NUM> and final burst seam <NUM>, thereby dissipating and decelerating the impulse of gas prior to its release into a personal airbag/cushion. Further, this embodiment may optionally include an elongated flexible tubular structure (not shown) located along the lumen of segmented tube <NUM> to maintain a consistent gas flow path along the length of segmented tube <NUM>. Flexible tubular structure <NUM> could be in the shape of a coiled spiral tube, such that inflator discharge gas can travel through and between each coil of its spiral structure.

The embodiment depicted in <FIG> can alternatively employ sealed, sacrificial burst seams <NUM> based on a similar principle described above for when the burst seam <NUM> is partially open; however, the use of sacrificial burst seams <NUM> would provide even further restriction to gas flow, thereby further dissipating and decelerating the impulse of inflator discharge gas.

Alternatively, burst seam <NUM> may be configured as a one way valve, such that inflator discharge gas would open the burst seam, and flow in the direction opposite the discharge flow would close the valve. In this configuration, the valve-type burst seam <NUM> would provide dual purposes of restricting and dissipating the impulse of inflator discharge gas and also preventing backflow of inflator discharge gas.

Regardless of the type of burst seam <NUM> used, sequential chambers <NUM> may be variable in size, such that a chamber near the inflator defines, for example, a larger volume than a chamber towards the opposite end of segmented tube <NUM>, thereby allowing for greater expansion of inflator discharge gas nearer the at least one inflator discharge port <NUM>.

Referring to <FIG>, another illustrative inflator and noise suppression assembly is depicted, in which an inflator <NUM> with at least one inflator discharge port <NUM> is surrounded by housing <NUM> defining an air chamber <NUM> between the inner surface of housing <NUM> and the outer surface of inflator <NUM>. The housing <NUM> may be concentric around the inflator <NUM>. Further, housing <NUM> is sealably affixed at or near one of end of inflator <NUM>, such that, upon activation of inflator <NUM> as necessary to inflate a personal airbag/cushion, inflator discharge gas is forcibly directed through air chamber <NUM> and exits through housing discharge port <NUM>. Air chamber <NUM> may incorporate internal baffling elements <NUM>, which dissipate and decelerate the impulse of inflator discharge gas and also reduce noise through the principle of resonant absorption. It should be appreciated by those skilled in the art that internal baffling elements <NUM> can be replaced with or used in combination with other means and materials for noise attenuation, such as a porous metal foam diffuser element <NUM> situated at or near concentric housing discharge port <NUM>.

An alternative embodiment is depicted in <FIG>, which replaces internal baffling elements <NUM> with a unitary porous diffuser tube <NUM>, such that inflator discharge gas is forcibly directed through diffuser tube <NUM> prior to exiting via concentric housing discharge port <NUM>.

Referring to <FIG>, another illustrative inflator and noise suppression assembly is depicted, in which an inflator <NUM> with at least one inflator discharge port <NUM> is affixed to housing <NUM>. Housing <NUM> is securely affixed to a flexible non-permeable inner tube <NUM>, which provides an elongated first chamber <NUM> to receive inflator discharge gas. Further, inner tube <NUM>, at its end opposite from housing <NUM>, is securely affixed to an end cap <NUM> containing at least one air channel <NUM>. End cap <NUM> is further affixed to flexible outer tube <NUM>, which surrounds the inner tube <NUM> and serves to provide an elongated second chamber <NUM>, which communicates with the at least one air channel <NUM>. The flexible outer tube <NUM> may be concentric with the flexible non-permeable inner tube <NUM>. Outer tube <NUM> terminates at or near inflator housing <NUM> and is securely affixed to inner tube <NUM> with a non-permeable sealing member <NUM>. Further, outer tube <NUM> contains at least one outer tube discharge port <NUM>, which communicates with second chamber <NUM>. End cap <NUM> may optionally contain elements to provide resonant absorption such as internal baffling elements <NUM> depicted in <FIG>.

Referring still to <FIG>, upon inflator activation as necessary to inflate a personal airbag/cushion, inflator discharge gas is released from housing discharge port <NUM> and expands into first chamber <NUM>, thereby at least partially dissipating the impulse of inflator discharge gas. Inflator discharge gas further travels into end cap <NUM> and through the at least one air channel <NUM>, which provides further restrictive dissipation of inflator discharge gas. Inflator discharge gas then expands further into second chamber <NUM>, thereby further dissipating the impulse of inflator discharge gas, prior to releasing into a personal airbag/cushion.

It should be appreciated by those skilled in the art that with each gas expansion chamber, redirection of gas, baffling elements, and restrictive element within the gas flow path, the impulse of inflator discharge gas is further dissipated and decelerated, thereby further suppressing the inflator discharge noise. Thus, the embodiment shown in <FIG> can optionally be expanded to include additional flexible concentric tubes which provide additional expansion chambers, connected in series to one another via additional air channels <NUM> incorporated into end caps <NUM>, which are employed at each end of the construct.

In a similar fashion, <FIG> depicts an alternative to the embodiment disclosed in <FIG>, whereby an additional flexible outer tube <NUM> with at least one outer tube discharge port <NUM> is incorporated to provide a further expansion chamber and further gas redirection prior to allowing inflator discharge gas to be released into a personal airbag/cushion.

Referring still to <FIG>, if outer tube <NUM> contains more than one outer tube discharge port <NUM>, each port may optionally have variable restrictive capacity, such that the pressure and inflator gas discharge rate at each port would be approximately similar along the lengths of inner tube <NUM> and outer tube <NUM>. Variable restrictive capacity could be accomplished, for example, by having smaller diameters of outer tube discharge port <NUM> toward the inflator <NUM> and progressively larger diameters toward the end opposite inflator <NUM>. This principle may be applied to any embodiment within this disclosure which utilizes a plurality of gas discharge ports and/or gas diffuser elements within a tube along which inflator discharge gas is directed to flow.

Likewise, <FIG>. depicts an alternative to the embodiment disclosed in <FIG>, whereby an additional flexible outer tube <NUM> with at least one outer tube discharge port <NUM> is incorporated to provide a further expansion chamber and further gas redirection prior to allowing inflator discharge gas to be released into a personal airbag/cushion.

It should be appreciated by those skilled in the art that while embodiments in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG> are shown in a straightened configuration for the purposes of illustrating their cross-sectional geometries, each of these embodiments will have an overall flexibility suitable to comfortably conform to the outer contours of human anatomy when comprised within a personal impact protection system. Further, this overall flexibility would enable each of these embodiments to be substantially collapsible in a pre-deployed state, and upon inflation, expandable to a deployed state. Such expansion would in itself dynamically create a defined volume within each expanded chamber for inflator discharge gas to expand, thereby at least partially dissipating and decelerating the impulse of inflator discharge gas.

Referring now to <FIG>, the embodiment depicted in <FIG>. is shown assembled within a personal airbag/cushion <NUM> which defines an airbag chamber <NUM>. It should be appreciated by those skilled in the art such a noise suppressor device assembled within a personal airbag/cushion <NUM> would provide further noise attenuation effects. This would be accomplished as follows. Upon inflator activation as necessary to inflate a personal airbag/cushion, as inflator discharge gas progresses down the lumen of inner tube <NUM>, it is incrementally released through outer tube discharge ports <NUM>, beginning nearer housing <NUM> and progressing towards the end opposite housing <NUM>. This progressive discharge gradually increases the pressure within airbag chamber <NUM>, such that, upon release of the impulse of inflator discharge gas, the pressure differential between the airbag chamber <NUM> and at the outer tube discharge port <NUM> is reduced. Since the sound is proportional to this pressure differential, reducing this differential further suppresses the noise caused by discharging the inflator.

Claim 1:
A system comprising:
an inflator (<NUM>) having an inflator discharge port (<NUM>);
an inner tube (<NUM>) configured to receive gas from the inflator (<NUM>) via the inflator discharge port (<NUM>); and
an outer tube (<NUM>) surrounding the inner tube (<NUM>) and configured to receive gas from the inner tube (<NUM>);
characterized in that:
the inner tube (<NUM>) is a flexible permeable inner tube (<NUM>) that comprises a woven polyester, nylon, Kevlar, or metallic fiber; and
the outer tube (<NUM>) is a flexible outer tube (<NUM>) that comprises a woven polyester, nylon, or Kevlar and includes one or more outer tube discharge ports (<NUM>).