Patent Description:
The use of hearing protective and noise attenuating devices are well known, and various types of devices have been considered. Such devices include earplugs and semi-aural devices partially or completely constructed of foam or rubber materials that are inserted into, or placed over, the ear canal of a user to physically obstruct the passage of sound waves into the inner ear.

Compressible or "roll-down" type earplugs generally comprise a compressible, resilient body portion and may be made of suitable slow recovery foam materials. The earplug may be inserted into the ear canal of a user by first rolling it between fingers to compress the body portion, then pushing the body portion into the ear canal, and subsequently allowing the body portion to expand to fill the ear canal.

Push-to-fit type earplugs have also been considered, and may include a compressible attenuating portion and a stiff portion that extends from the attenuating portion. <CIT> discloses a hearing protection device insertable into an earcanal, the device generally including a stem portion, a sound attenuating portion affixed to and extending at least partially over the stem portion, and a volume of space disposed between and delimited by the sound attenuating portion and the stem portion, where at least a part of the sound attenuating portion is collapsible into the volume of space during insertion of the hearing protection device into the earcanal. To insert a push-to-fit type earplug, the user grasps the stiff portion and pushes the attenuating portion into the ear canal with an appropriate level of force. The attenuating portion compresses as it is accommodated in the ear canal. Push-to-fit earplugs may allow the earplug to be quickly and easily inserted in an ear canal, and may promote hygiene by minimizing contact with the attenuating portion of the earplug prior to insertion.

The present description relates to an earplug, such as a push-to-fit earplug. In an embodiment, an earplug includes a stem and a sound attenuating body attached to the stem. The sound attenuating body includes a leading end, a base end, a tip region positioned rearward of the leading end, and a longitudinal axis extending between the leading end and the base end. An array of cavities is positioned within the tip region and spaced around the longitudinal axis, and the array of cavities provides a collapsible volume. The tip region comprises a cavity area (Ac), a material area (Am) and an area aspect ratio (Ac/Am) at a plane intersecting the array of cavities transverse to the longitudinal axis, and <NUM> < (Ac/Am) < <NUM>.

In an particular exemplary embodiment, the sound attenuating body further includes a flange extending at least partially over the stem and comprising an exterior flange surface and an interior flange surface having a plurality of one or both of protrusions or recesses and the earplug further includes a flange cavity including a continuous volume around a perimeter of the stem between the interior flange surface and the stem.

The above summary is not intended to describe each disclosed embodiment or every implementation. The Figures and the Detailed Description, which follow, more particularly exemplify illustrative embodiments.

The disclosure may be further explained with reference to the appended Figures, wherein like structure is referred to by like numerals throughout the several views, and wherein:.

While the above-identified figures set forth various embodiments of the disclosed subject matter, other embodiments are also contemplated. In all cases, this disclosure presents the disclosed subject matter by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art which fall within the scope of the claims.

An earplug that provides hearing protection for a user is provided herein. An earplug according to the present disclosure includes a stem and a sound attenuating body having a flange. When inserted into the ear canal of a user, the sound attenuating body is able to compress and at least partially collapse into a collapsible volume provided by an array of cavities in a tip region. The array of cavities provide additional volume into which a portion of the sound attenuating body can collapse, reducing an insertion force required to position the earplug in an ear canal and reducing an equilibrium force exerted by the earplug and acting on a user's ear canal when the earplug is positioned for use. An earplug having an array of cavities in a tip region as described herein facilitates an earplug that is easy to insert and comfortable to wear.

<FIG> show an exemplary push-to-fit earplug <NUM> including a stem <NUM> and sound attenuating body <NUM> and having first and second ends <NUM> and <NUM>. Sound attenuating body <NUM> is configured for at least partial insertion into the ear canal of a user to attenuate the passage of sound into the ear canal. During insertion of earplug <NUM>, stem <NUM> may serve as a handle which may be gripped by a user. Earplug <NUM>, and specifically sound attenuating body <NUM>, is brought proximate to the user's ear and at least partially inserted into the ear canal. Sound attenuating body <NUM> compresses and/or collapses as it is positioned, and stem <NUM> provides sufficient stiffness to facilitate insertion. In use, sound attenuating body <NUM> is positioned substantially within an ear canal to block the passage of sound and stem <NUM> extends outwardly from the ear canal to provide a handle to remove the earplug.

In an exemplary embodiment, sound attenuating body <NUM> includes a leading end <NUM>, a base end <NUM>, a tip region <NUM> and a flange <NUM> extending at least partially over stem <NUM>. Tip region <NUM> is located rearwardly of leading end <NUM> and flange <NUM> is located between tip region <NUM> and base end <NUM>. In some exemplary embodiments, sound attenuating body <NUM> defines a flange cavity <NUM> between stem <NUM> and sound attenuating body <NUM>. In an exemplary embodiment, flange cavity <NUM> is defined at least in part by stem <NUM>, sound attenuating body <NUM>, and a flange cavity bottom <NUM>. Flange cavity bottom <NUM> may be formed by a portion of tip region <NUM>, where stem <NUM> and sound attenuating body <NUM> intersect, for example.

Certain features of an earplug according to the present description may be understood in view of various reference planes defined relative to earplug <NUM> and shown in <FIG>. A longitudinal axis <NUM> extends between leading end <NUM> and base end <NUM> of sound attenuating body <NUM>. A leading end plane <NUM> passes across an outermost tip of leading end <NUM>, and/or first end <NUM>, of earplug <NUM> transverse to the longitudinal axis, and a flange end plane <NUM> intersects earplug <NUM> transverse to longitudinal axis <NUM> at base end <NUM> of flange <NUM>. In various exemplary embodiments, a cavity plane <NUM> intersects earplug <NUM> at a forward-most portion of flange cavity <NUM>.

In an exemplary embodiment, flange <NUM> is not attached to stem <NUM> within flange cavity <NUM>, or between cavity plane <NUM> and base end <NUM>, and only attaches to stem at and/or above cavity plane <NUM>. Flange <NUM> may be defined as that portion of sound attenuating body <NUM> that is located below the cavity plane <NUM>. Because flange <NUM> is connected to a remainder of sound attenuating body <NUM> and/or stem <NUM> only near one end, flange cavity <NUM> includes a continuous volume around stem <NUM>. According to the invention, an interior flange surface <NUM> of flange <NUM> does not contact stem <NUM> when in a neutral, uncompressed configuration such as when not positioned in an ear canal. In an exemplary embodiment, the flange cavity includes a continuous uninterrupted volume around a perimeter of at least a portion of stem <NUM>. Flange <NUM> may deflect inwardly as earplug <NUM> is advanced into an ear canal and/or is positioned therein, and in some embodiments interior flange surface <NUM> may at least partially contact stem <NUM>. In various exemplary embodiments, deflection and/or compression of flange <NUM> may improve insertion, comfort, and sound attenuation, and may be controlled by the materials, geometry, and configuration of earplug <NUM>.

Earplug <NUM> includes an array of cavities <NUM> positioned within tip region <NUM> and spaced around the longitudinal axis <NUM>. Cavities <NUM> provide a collapsible volume that at least a portion of sound attenuating body <NUM> may collapse into as earplug <NUM> is advanced into an ear canal of a user. Collapsible volume provided by cavities <NUM> provides an earplug <NUM> that may be comfortably inserted and worn by a user while providing a desired level of sound attenuation. The geometry and configuration of cavities <NUM> may be selected as described herein to provide a desire balance of fit for a range of users having varied ear canal shapes and sizes.

Cavities <NUM> may be positioned around longitudinal axis <NUM> and extend within tip region <NUM> of earplug <NUM>. In an exemplary embodiment, earplug <NUM> includes a flange cavity <NUM> between stem <NUM> and sound attenuating body <NUM> and having a flange cavity bottom <NUM>. Cavities <NUM> are positioned between flange cavity bottom <NUM> and leading end <NUM> of sound attenuating body <NUM> (e.g. between cavity plane <NUM> and leading end plane <NUM>).

In an exemplary embodiment, the array of cavities <NUM> extend between first and second cavity ends <NUM> and <NUM> and have a generally elongate shape. First cavity end <NUM> may be the forward-most portion of array of cavities <NUM> nearest to leading end <NUM> and second cavity end <NUM> may be the rearward-most portion of array of cavities <NUM> furthest from leading end <NUM>. In various exemplary embodiments, cavities <NUM> have a length (Lc) between first and second cavity ends <NUM> and <NUM> between about <NUM> and <NUM>, <NUM> and <NUM>, or of about <NUM>.

In an exemplary embodiment, first cavity end <NUM> is between <NUM> and <NUM>, <NUM> and <NUM>, or about <NUM> from leading end <NUM> of sound attenuating body <NUM>. Such a distance allows for sufficient stiffness such that leading end <NUM> may be readily inserted into a user's ear. Second cavity end <NUM> is at least partially open and in communication with flange cavity <NUM>, and second cavity end <NUM> may be located proximate cavity plane <NUM>.

Array of cavities <NUM> are sized to provide a desirable collapsible space to reduce a force required to compress sound attenuating body <NUM> when earplug <NUM> is at least partially inserted into an ear canal of a user. In various exemplary embodiments, such as shown in <FIG>, tip region <NUM> of sound attenuating body <NUM> may be characterized as having a cavity area (Ac) and a material area (Am) at a plane intersecting array of cavities <NUM> transverse to the longitudinal axis, such as plane <NUM>. Cavity area (Ac) is an area of open space within each cavity <NUM>, and material area (Am) is the remaining area of tip region <NUM> of earplug <NUM> including material, such as foam material and cells that may be present in the material. In various exemplary embodiments, cavity area (Ac) may be between <NUM><NUM> and <NUM><NUM>, <NUM><NUM> and <NUM><NUM>, or about <NUM><NUM>, and material area (Am) may be about <NUM><NUM> to <NUM><NUM>, <NUM><NUM> to <NUM><NUM>, or about <NUM><NUM>.

In an exemplary embodiment, array of cavities <NUM> exhibits an area aspect ratio (Ac/Am) of cavity area (Ac) to material area (Am). In various exemplary embodiments, (Ac/Am) is between <NUM> and <NUM>, <NUM> and <NUM>, or about <NUM>, and in some exemplary embodiments may exhibit an area aspect ratio (Ac/Am) within such ranges when plane <NUM> passes through array of cavities at a distance between <NUM> and <NUM> from leading end <NUM>. A maximum area aspect ratio (Ac/Am) exists at a plane passing through array of cavities transverse to longitudinal axis <NUM> at a location in which (Ac/Am) is greatest. In an exemplary embodiment, maximum area aspect ratio (Ac/Am) at plane <NUM> intersecting array of cavities <NUM> at a distance between <NUM> and <NUM> is between <NUM> and <NUM>, <NUM> and <NUM>, or about <NUM>. In various exemplary embodiments, maximum area aspect ratio (Ac/Am) occurs at second end <NUM>, for example at cavity plane <NUM>, and the cavities taper such that (Ac/Am) decreases at locations closer to first end <NUM> of array of cavities <NUM>.

Array of cavities <NUM> result in a reduced wall thickness (Tw) between an interior surface <NUM> of cavity <NUM> and an exterior surface <NUM> of tip region <NUM>. Reduced wall thickness (Tw) may be selected to provide a required level of durability such that earplug does not readily tear or break while also not being so thick so as to unduly increase equilibrium force. In various exemplary embodiments, reduced wall thickness is between <NUM> and <NUM>, <NUM> and <NUM>, or about <NUM>.

An exemplary earplug <NUM> having dimensions and cavity area (Ac) within the above ranges provides additional collapsible space for material of tip region <NUM> to compress into as tip region <NUM> is positioned and resident in an ear canal of a user. In an exemplary embodiment, such ranges may result in a desired equilibrium force exerted by tip region <NUM> when residing in an ear canal of a user. Equilibrium force is a force exerted by earplug <NUM> to return to an original, uncompressed state and is related to a force exerted on a user's ear canal when earplug <NUM> is positioned for use. Accordingly, array of cavities <NUM> having a cavity area (Ac) within such ranges provides a reduced equilibrium force to maximize comfort while ensuring sufficient force that earplug <NUM> may be maintained in position in a user's ear canal. In various exemplary embodiments, array of cavities <NUM> can reduce equilibrium force between <NUM> % and <NUM> %, <NUM> % and <NUM> %, or about <NUM> % as compared to an earplug having the same material and geometry but not having an array of cavities.

Array of cavities <NUM> may include any suitable number and shape of cavities. In various exemplary embodiments, array of cavities <NUM> includes between <NUM> and <NUM>, <NUM> and <NUM>, or about <NUM> cavities <NUM>. Cavities <NUM> may have any desired cross-sectional shape and may vary along a length of the cavities, for example between first and second cavity ends <NUM>, <NUM>. In an exemplary embodiment of <FIG>, cavities <NUM> have a generally trapezoidal shape, and is only one example of many suitable shapes for cavities as described herein. Other exemplary shapes, include, but are not limited to, the shapes of <FIG> show earplugs <NUM> and <NUM> having an array of cavities <NUM>, <NUM> that exhibit oval, or otherwise arcuate, and quadrilateral cavities.

An exemplary earplug as described herein may have any suitable shape or profile to provide a desired fit or that may be suitable for a particular application. The specific shape of sound attenuating body <NUM> of the exemplary embodiment depicted in <FIG> is only one example of a potentially suitable shape for an earplug as described herein. Examples of one of the myriad of alternative shapes that could be used for earplugs as described herein is depicted in <FIG> showing exemplary earplug <NUM> having sound attenuating body <NUM>.

In some exemplary embodiments, a channel <NUM> extends through earplug <NUM> between first and second ends <NUM>, <NUM>. Earplugs as described herein that include channels passing through the earplug may be manufactured such that components of a receiver or of a communication system may be attached to the earplug. Alternatively or in addition, channel <NUM> may accommodate one or more filters or other passive hearing elements to provide an attenuation curve having a desired shape. For example, filters positioned in channel <NUM> may cause nonlinear attenuation of high level impulses produced by explosions, gunfire, or the like. Channels provided in one or more embodiments of earplugs as described herein may also provide a recess that a cord may be attached to, such that first and second earplugs may be joined, or that ends of a headband may be attached to in a semi-aural hearing protector.

Earplugs as described herein may be manufactured in any suitable manner. In an exemplary embodiment, earplug <NUM> includes a core <NUM> that provides a substrate onto which an outer layer of material may be provided and, in one or more embodiments, may facilitate insertion into an ear canal of a user. Core <NUM> is made of a first material that exhibits greater rigidity or stiffness than a second material that forms sound attenuating body <NUM>, yet that is soft enough to be comfortable and safe for a user. In an exemplary embodiment, the first material of core <NUM> is different than the second material used to form sound attenuating body <NUM> and/or an outer layer <NUM> of stem <NUM>. In other exemplary embodiments, the first and second materials are similar or the same chemically, but may be formed or provided in a manner that results in different stiffnesses between the first material and the second material, for example due to differing density, cell structure, hardness, etc..

Including a core <NUM> in the stem <NUM> that is stiffer than the material of sound attenuating body <NUM> and/or outer layer <NUM> of the stem <NUM> may, in one or more exemplary embodiments, provide a stem <NUM> having sufficient rigidity so that the earplugs described herein may be positioned for use at least partially in the ear of a user by pushing sound attenuating body <NUM> into the ear canal with an appropriate force. That is, a sufficiently stiff stem <NUM> may be provided by a core <NUM> and an outer layer <NUM> of the material used to form the sound attenuating body <NUM> so that earplug <NUM> may be positioned for use at least partially in the ear of a user without the need to first compress or "roll down" sound attenuating body <NUM>. Direct insertion without the need to first compress or "roll down" sound attenuating body <NUM> may, for example, promote hygiene by limiting contact with sound attenuating body <NUM> prior to placement in the ear. In one or more embodiments, core <NUM> may also exhibit an appropriate level of flexibility such that it may slightly deform to follow the contours of the ear canal when positioned for use.

Core <NUM> may, in one or more exemplary embodiments, be made from one or more materials that can suitably bond to, and are otherwise compatible with, the material used to form the sound attenuating body <NUM> and/or, when present, outer layer <NUM> of stem <NUM>. In one or more embodiments, core <NUM> may be made from a blend of polypropylene and styrene-ethylene-butylene-styrene (SEBS), such as TUFPRENE available from S&E Specialty Polymers, LLC. of Lunenburg, Massachusetts or PPC1TF2 available from Washington Penn Plastic Co. of Washington, Pennsylvania. Other potentially suitable materials include SANTOPRENE <NUM>-<NUM>, available from Exxon Mobile Corporation, and other materials exhibiting appropriate stiffness such that sound attenuating body <NUM> of earplug <NUM> may be easily inserted into the ear canal of a user.

A second material used to form sound attenuating body and, in one or more embodiments, an outer layer of a stem of an earplug as described herein, may be soft and pliable foam, rubber, polymer, or other suitable material that may be comfortably positioned in an ear canal of a user. In one or more exemplary embodiments, the second material is an SEBS, such as MONPRENE MP1900 available from Teknor Apex of Pawtucket, Rhode Island, or a blend of high and low molecular weight Kraton SEBS resins resulting in a hardness of <NUM> Shore A, available from Kraton Polymers LLC, of Houston, Texas, that provides a cellular foam. Other suitable materials include plasticized polyvinyl chloride, ethylene propylene diene monomer (EPDM) rubber, styrene butadiene rubber (SBR), butyl rubber, natural rubbers, other thermoplastics, thermoset polymers, and other suitable materials as known in the art that can be formulated to exhibit an appropriate hardness range.

In one or more embodiments, the materials used to construct a core and sound attenuating body may be selected such that the primary source of bonding between the core and material used for the sound attenuating body (directly or indirectly) is thermal bonding. In one or more embodiments, an additional adhesive is not required to bond the core to the sound attenuating body and, as a result, an adhesive is not present between the core and the sound attenuating body. Although the sound attenuating body of an earplug as described herein may be described as being constructed of a second material, in one or more embodiments a sound attenuating body may be constructed of multiple layers of the same or different materials (which may be, e.g., arranged concentrically). For example, a first layer may be used to provide desired characteristics for contacting an ear canal of a user and a second layer may be used to facilitate a robust bond with the core, while one or more additional layers may be used to provide other desired characteristics.

Materials used in the sound attenuating body of earplugs as described herein may be selected to control the friability of the outer surface of the sound attenuating bodies such that it may not easily be broken or disintegrate during use. The friability of an earplug may be controlled in part by selecting a material having an appropriate molecular weight, with higher molecular weight generally resulting in a less friable earplug. In an exemplary embodiment, sound attenuating body <NUM> includes an SEBS having a molecular weight between <NUM>,<NUM> Daltons and <NUM>,<NUM> Daltons, as measured by gel permeation chromatography analysis as known in the art, such as according to ASTM D6474 - <NUM>.

The density of outer layer of second material used in the sound attenuating bodies as used in earplugs as described herein can, in one or more embodiments, be controlled during manufacturing to provide a specified density as desired for a particular application. The second material may, in one or more embodiments, exhibit a density that varies by thickness, for example, such that the second material used in the sound attenuating body has an integral outer skin that has a higher density than the second material located closer to the core. Such a skin may be present on one or both of sound attenuating body and the stem (in embodiments in which the stem includes, for example, a layer of the second material used in the sound attenuating body). Alternatively, the second material used to construct the sound attenuating body and/or an outer layer of the stem may have a substantially uniform density. In various exemplary embodiments, the average density of the sound attenuating portion, comprising a foamed SEBS for example, is between <NUM>/m<NUM> and <NUM>/m<NUM>, or <NUM>/m<NUM> and <NUM>/m<NUM>, or may be about <NUM>/m<NUM>.

<CIT>, titled Method of Making an Earplug, addresses a method of making personal protective equipment such as a push-to-fit earplug, <CIT>, titled Push-In Earplug, addresses the structure and configuration of a push-to-fit earplug, and <CIT>, titled Foamable Article, addresses an article for forming a device or component.

In some exemplary embodiments, earplug <NUM> may be formed from a single material or first and second materials that are similar or the same chemically, but formed or provided in a manner that results in different stiffnesses between the first material and the second material, for example due to differing density, cell structure, hardness, etc. For example, a stem and sound attenuating body having differing properties may be formed by controlling venting in a molding process, and a core <NUM> may not be included. <CIT>, Molded Foam Push-To-Fit Earplug, Method, and Devices, , describes techniques for making an earplug having a sound attenuating body and stiffer stem formed from the same or similar materials.

In various exemplary embodiments, stem <NUM> and sound attenuating body <NUM> may be formed separately and subsequently joined together. For example, sound attenuating body <NUM> may be formed from any suitable soft and pliable foam, rubber, polymer, or other suitable material, as described above, and stem <NUM> may be formed of a more rigid material. Stem <NUM> and sound attenuating body <NUM> are then permanently or removably joined, for example by an adhesive, friction, or other engagement.

An earplug as described herein may include various other geometric features to enhance comfort or provide improved attenuation. <FIG> show an exemplary push-to-fit earplug <NUM> including a stem <NUM> and sound attenuating body <NUM> and having first and second ends <NUM> and <NUM>. Sound attenuating body <NUM> includes a leading end <NUM>, a base end <NUM>, a tip region <NUM> and a flange <NUM>. Tip region <NUM> is located rearwardly of leading end <NUM> and flange <NUM> is located between tip region <NUM> and base end <NUM>. Similar to exemplary earplug <NUM>, sound attenuating body <NUM> includes an array of cavities <NUM> positioned within tip region <NUM> and spaced around the longitudinal axis <NUM>. Cavities <NUM> provide a collapsible volume that at least a portion of sound attenuating body <NUM> may collapse into as earplug <NUM> is advanced into an ear canal of a user.

Exemplary earplug <NUM> includes a tip cavity <NUM> that extends from first end <NUM> of earplug <NUM> towards a bottom <NUM> located nearer second end <NUM> of earplug <NUM>. Tip cavity <NUM> includes an opening at first end <NUM> of earplug <NUM>. Tip cavity <NUM> may, in one or more exemplary embodiments, provide a volume into which the surrounding material of sound attenuating body <NUM>, and particularly tip region <NUM>, can collapse as earplug <NUM> is advanced into an earcanal and/or is resident therein. <CIT>, Earplug with Tip Cavity and Methods of Manufacturing the Same address earplugs having a tip cavity.

In an exemplary embodiment, bottom <NUM> of tip cavity <NUM> may be spaced from a first end <NUM> of cavities <NUM>. For example, bottom <NUM> of tip cavity <NUM> may be spaced a distance (dmin) from a portion of cavities <NUM>, such as first end <NUM> of cavities <NUM>. In various exemplary embodiments, a minimum distance (dmin) between tip cavity <NUM> and one or more cavities <NUM> is between at least <NUM> and <NUM>, <NUM> and <NUM>, or of about <NUM>. A minimum distance (dmin) within such ranges results in a sufficient stiffness such that a leading end <NUM> of earplug <NUM> may be inserted in a user's ear, and improves strength and durability to withstand repeated uses.

In an exemplary embodiment, earplug <NUM> further includes various geometric features <NUM> of an interior flange surface <NUM> such that a distance between exterior and interior flange surface <NUM>, <NUM> varies and flange <NUM> exhibits different thickness around a perimeter of the flange at a plane intersecting the flange transverse to the longitudinal axis. For example, flange <NUM> may be characterized by a minimum flange thickness (Fmin) and a maximum flange thickness (Fmax) between exterior flange surface <NUM> and interior flange surface <NUM>. In an exemplary embodiment, flange <NUM> includes a plurality of geometric features in the form of splines <NUM> spaced about flange <NUM> and extending from base end <NUM> of flange <NUM> at least partially towards bottom <NUM> of flange cavity <NUM>. Splines <NUM> exhibit a width (w) between two adjacent locations of a minimum flange thickness (Fmin). Geometric features, such as protrusions, recess, or splines <NUM>, affect collapse and/or compression of flange <NUM> such that undesirable creasing or buckling of flange <NUM> is minimized. An earplug having such geometric flange features facilitates an earplug that is comfortable to wear and minimizes undue noise leakage into an ear canal by limiting creasing or buckling of the flange. <CIT>, Push-To-Fit Earplug Having Geometric Flange Features, addresses earplugs having a plurality of inwardly projecting geometric features.

The present invention has now been described with reference to several embodiments thereof. The foregoing detailed description and examples have been given for clarity of understanding only. No unnecessary limitations are to be understood therefrom. It will be apparent to those skilled in the art that many changes can be made in the embodiments described without departing from the scope of the invention. Thus, the scope of the present invention should not be limited to the exact details and structures described herein, but rather by the structures described by the language of the claims.

Any feature or characteristic described with respect to any of the above embodiments can be incorporated individually or in combination with any other feature or characteristic, and are presented in the above order and combinations for clarity only. That is, the present disclosure contemplates all possible combinations and arrangements of various features of each of the exemplary embodiments and components describe herein, and each component may be combined or used in conjunction with any other component as may be desired for a particular application.

The characteristics, operation, and advantages of the present invention may be further understood with regard to the following detailed non-limiting examples. These examples are offered to further illustrate the various specific and preferred embodiments and techniques. It should be understood, however that many variations and modifications may be made while remaining within the scope of the present invention.

Equilibrium force is a rebound force exerted by an earplug when compressed and represents a force exerted by an earplug when positioned in a user's ear canal. Equilibrium force may provide an indication of a relative level of comfort of an earplug.

Equilibrium force was obtained by placing an earplug conditioned in an environmental room set to <NUM> (<NUM> °F) and <NUM> percent relative humidity for <NUM> hours between parallel feet having matching straight edges of <NUM> (<NUM> inches) of a Chatillon DGGS Force Gauge (<NUM> gm - <NUM> gm) mounted on an LTS stand. The parallel feet were adjusted using a <NUM> (<NUM> inch) calibration pin placed between the feet such that spacing between the feet was <NUM> (<NUM> inches) and a force reading between <NUM> to <NUM> grams was obtained. The force gauge was positioned in a temperature chamber capable of controlling to <NUM> ± <NUM> (<NUM>°F ± <NUM> °F). After the temperature chamber reached <NUM> ± <NUM> (<NUM> °F ± <NUM> °F) for <NUM> minutes, a maximum force measured in <NUM> second intervals was recorded for <NUM> minutes. The average of the maximum forces measured in each <NUM> second interval represented the equilibrium force.

A leading end of an earplug is adhered in a <NUM> diameter and <NUM> deep recess of a fixture using LOCTITE <NUM> cyanoacrylate adhesive. The fixture was mounted onto a Model <NUM> tensile machine available from Instron of Norwood, MA, and the vertically oriented stem portion was clamped in pneumatic jaws of the tensile machine. The tensile machine was programmed to pull the fixture and pneumatic jaws until a force of <NUM> (<NUM> lbs) was achieved and then return to a home position. The home position was maintained for approximately <NUM> seconds and the tensile machine again pulled to a force of <NUM> (<NUM> lbs). The process was repeated for <NUM> cycles or until failure.

The sample of Examples <NUM>, <NUM> and Comparative Example A included a core made from PPC1TF2 Pantone 307C (serial # <NUM>) from Washington Penn Plastic Co. of Frankfort, Kentucky and a sound attenuating portion and stem outer layer made from Kraton SEBS resins with a hardness of <NUM> Shore A, from Kraton Polymers LLC, of Houston, Texas, and included expanded spheres and a chemical foaming agent. The core was coated with the material of the sound attenuating portion and stem outer layer and subsequently placed in a mold and heated to form a sound attenuating portion. The earplug of Example <NUM> included an array of cavities including <NUM> cavities having trapezoidal cross-sectional shapes uniformly spaced around the longitudinal axis with a shape and configuration shown in <FIG> and <FIG>. The earplug of Example <NUM> had a shape and configuration shown in <FIG> and <FIG> and included an array of cavities including <NUM> cavities having generally rectangular cross-sectional shapes uniformly spaced around the longitudinal axis. The earplug of Comparative Example A had a shape and configuration shown in <FIG> and <FIG> but did not include an array of cavities.

The dimensions of the earplugs of Examples <NUM> and <NUM> and Comparative Example A are summarized in Table <NUM>. Cavity wall thickness (Tw) was measured at a plane intersecting the array of cavities at a distance (L4) from the leading end.

Results of the Equilibrium Force Test and Fatigue Cycle Test are reported in Table <NUM> below. Examples <NUM> and <NUM> including an array of cavities having a cavity area (Ac) of <NUM><NUM> and <NUM><NUM>, respectively, at a distance L5 from the leading end, showed a <NUM> percent and <NUM> percent reduction in equilibrium force as compared to Comparative Example A, while successfully completing the Fatigue Cycle Test. Accordingly, Examples <NUM> and <NUM> having an array of cavities reduced the equilibrium force exerted by the earplug and thus are likely to provide a comfortable fit for a user, particularly if worn for an extended period of time. Further, the array of cavities resulted in a reduced equilibrium force while maintaining sufficient durability to pass the Fatigue Cycle Test and not fail after <NUM> cycles.

Claim 1:
An earplug (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>), comprising:
a stem (<NUM>, <NUM>);
a sound attenuating body (<NUM>, <NUM>, <NUM>) attached to the stem, the sound attenuating body comprising a leading end (<NUM>, <NUM>), a base end (<NUM>, <NUM>), a tip region (<NUM>, <NUM>) positioned rearward of the leading end, a flange between the tip region and the base end and extending at least partially over the stem, the flange comprising an exterior flange surface (<NUM>, <NUM>) and an interior flange surface (<NUM>, <NUM>) that does not contact the stem when in a neutral, uncompressed configuration, and a longitudinal axis (<NUM>) extending between the leading end and the base end; and
a flange cavity comprising a continuous volume between the flange and the stem around a perimeter of the stem; characterised by
an array of cavities (<NUM>, <NUM>, <NUM>, <NUM>) positioned within the tip region and spaced around the longitudinal axis, the array of cavities comprising a collapsible volume;
wherein in the tip region at a plane (<NUM>) intersecting the array of cavities transverse to the longitudinal axis, each cavity has an area of open space within said cavity, the sum of said areas being a cavity area of the array of cavities (Ac) and wherein at said plane (<NUM>) intersecting the array of cavities transverse to the longitudinal axis the tip region comprises a material area (Am), the material area (Am) being the remaining area of tip region of the earplug, and an area aspect ratio (Ac/Am), and <NUM> < (Ac/Am) < <NUM>.