Background

Head harnesses have often found use in securing a respirator mask (e.g. a full face respirator) to the head of a human wearer.

Summary

In broad summary, herein is disclosed a harness for use with a respirator mask, the harness exhibiting a generally bowl-shaped central core with a plurality of straps radiating from the central core. The harness comprises a generally ring-shaped, concave reinforcing frame that is at least partially embedded within a central portion of a single, integral piece of molded compliant material. These and other aspects will be apparent from the detailed description below. In no event, however, should this broad summary be construed to limit the claimable subject matter, whether such subject matter is presented in claims in the application as initially filed or in claims that are amended or otherwise presented in prosecution.

Brief Description of the Drawings

Fig. 1 is a front-right perspective view of an exemplary head harness as disclosed herein.

Fig. 2 is a right-rear perspective view of the head harness of Fig. 1.

Fig. 3 is a rear view of the head harness of Fig. 1.

Fig. 4 is a perspective view of the head harness of Fig. 1 and a respirator mask with which the head harness may be used.

Fig. 5 is a side view of the head harness of Fig. 1.

Fig . 6 is a front-right perspective view of a portion of the head harness of Fig . 1 , with an exemplary embedded reinforcing frame depicted within a molded compliant material of the head harness.

Fig. 7 is a front-right perspective view showing the embedded reinforcing frame of Fig. 6, with the reinforcing frame having been exploded, along a forward-rearward direction, away from the molded compliant material of the head harness.

Fig. 8 is an isolated left-rear perspective view of the reinforcing frame of Fig. 6.

Fig. 9 is an isolated side view of the reinforcing frame of Fig. 6.

Fig. 10 is an isolated magnified exploded view of a top strap, a top clip, and an associated top fastener to which the top clip can be mated.

Like reference numbers in the various figures indicate like elements. Some elements may be present in identical or equivalent multiples; in such cases only one or more representative elements may be designated by a reference number but it will be understood that such reference numbers apply to all such identical elements. Unless otherwise indicated, all figures and drawings are not to scale and are chosen for the purpose of illustrating different embodiments of the invention. In particular the dimensions of the various components are depicted in illustrative terms only, and no relationship between the dimensions of the various components should be inferred from the drawings, unless so indicated.

Although terms such as “first” and “second” may be used in this disclosure, it should be understood that those terms are used in their relative sense only unless otherwise noted. As used herein as a modifier to a property or attribute, the term “generally”, unless otherwise specifically defined, means that the property or attribute would be readily recognizable by a person of ordinary skill but without requiring a high degree of approximation (e.g., within +/- 20 % for quantifiable properties). The term “substantially”, unless otherwise specifically defined, means to a high degree of approximation (e.g., within +/- 10% for quantifiable properties). The term “essentially” means to a very high degree of approximation (e.g., within plus or minus 2 % for quantifiable properties); it will be understood that the phrase “at least essentially” subsumes the specific case of an “exact” match. However, even an “exact” match, or any other characterization using terms such as e.g. same, equal, identical, uniform, constant, and the like, will be understood to be within the usual tolerances or measuring error applicable to the particular circumstance rather than requiring absolute precision or a perfect match.

As used herein, the vertical axis and upward and downward directions along the vertical axis have their ordinary meaning with respect to a head harness (and associated respirator mask) worn on the head of an upright human user. Similarly, the lateral axis and right and left directions along the lateral axis have their usual meanings with reference to a head harness worn on the head of an upright human user. Terms such as forward and rearward as used with respect to a head harness and components thereof, respectively imply directions toward, and away from, the head of the user. The vertical, lateral, and/or forward-rearward axes are indicated in various Figures herein. The term “configured to” and like terms is at least as restrictive as the term “adapted to”, and requires actual design intention to perform the specified function rather than mere physical capability of performing such a function. All references herein to numerical values (e.g. dimensions, ratios, and so on), unless otherwise noted, are understood to be calculable as average values derived from an appropriate number of measurements.

Detailed Description

Disclosed herein is a head harness 1, configured for use with a respirator mask (e.g. a full face respirator mask) as worn by a human user. Exemplary harness 1 is shown in Figs. 1 and 2 in front and rear perspective views, in Fig. 3 in rear view, and in Fig. 5 in side view. Hamess 1 will typically comprise a generally forward major surface 7 (portions of which may be in contact with the wearer’s head) and an opposing, generally rearward major surface 8. Hamess 1 has a generally bowl-shaped central core 2 that is oriented concave-forward and is configured (e.g. shaped and sized) to be positioned snugly against the rear surface of the head of a human user. Hamess 1 also has a plurality (e.g. three, four, five, or more) of straps (arms) that radiate from the central core in various directions. In the exemplary embodiments depicted in these Figures, these harness straps take the form of left and right upper side straps 3 and 3’, left and right lower side straps 4 and 4’, and a single top strap 5. When viewed along the forward-rearward axis of the harness (as in Fig. 3), the top strap extends in an upward direction, the upper side straps extend oppositely along an approximately horizontal direction, and the lower side straps extend at slightly downward angles. It will be appreciated that the number and orientation of the harness straps may be varied as desired.

As depicted in exemplary embodiment in Fig. 4, head harness 1 is configured for use with a respirator mask (e.g. a full face respirator mask) 100 in order to hold the respirator mask securely against the wearer’s face. Such a respirator mask can provide breathing protection for a human user, e.g. by accepting air from an air supply and/or by having one or more air-filtration cartridges fitted thereto. Such a respirator mask may also provide physical protection, protection of the wearer’s eyes from electromagnetic radiation, and so on, as will be well understood by artisans in the field. Such a respirator mask 100 will typically comprise a lens 101 through which the wearer can see, a seal 108 that allows the mask to achieve a suitable fit against the wearer’s face, and an assortment of straps, buckles and so on. In the depicted embodiment, mask 100 comprises a top band (strap) 102 with a fastener 103 that is complementary with fastener (e.g., clip) 36 of top strap 5 of harness 1. Mask 100 further comprises an upper left band 104 with a buckle 105, and a lower left band 106 with a similar buckle 107 (similar upper and lower right bands and buckles will be present but are not visible in Fig. 4). In the depicted configuration, buckles 105 and 107 each comprise one or more through-passages (e.g. slots extending transversely across the width of the buckle) through which an end section of strap 3 and 4 of harness 1 can be threaded in a serpentine manner and held therein by friction. In some embodiments, the terminal ends 31 of such harness straps can have a suitable shape (e.g. a general “trefoil” shape as in Fig. 4) to enhance this holding (and/or to enhance the ability of the terminal ends to be grasped by fingers). It will be appreciated, however, that any suitable securing or fastening system may be used to secure a strap of a harness to a corresponding band of a respirator mask. In some instances such a fastening system may rely on a tongued buckle. In other embodiments a set of complementary fastening clips 36 and 103 may be used, e.g. as is done with top strap 5 and top band 102, as seen in Fig. 4 and as shown in magnified isolated view in Fig. 10.

Central core 2 of harness 1 is generally bowl-shaped. By this is meant that core 2 is generally concave, with the concave opening facing forward (toward the head of a wearer), as evident in Fig. 4. By generally bowl-shaped, and by having a concave, forward-facing opening, is meant that the central core of harness 1 will stably exhibit such a shape in the absence of any external support. That is, to qualify as bowlshaped in this context, it is not sufficient that an item can be deformed from a flat state into a bowl shape and held there; rather, the item itself must maintain this general shape without external support. In the simplest case, a harness can be placed on a horizontal surface (e.g. a tabletop), concave side up. If the putative “core” maintains a three-dimensional shape that is in the general form of a bowl, it qualifies under the definition used herein. If it collapses flat (or e.g. into a shapeless mass in which no bowl shape is readily apparent), it does not. The term generally bowl-shaped does not require that central core 2 must exhibit a perimeter that is a perfect circle when viewed along the forward-rearward axis of the harness. In some embodiments, the perimeter of core 2 may indeed be circular or near-circular when viewed along this axis. However, in some embodiments, a central core may exhibit an outer perimeter that is in the general form of a polygon in which multiple relatively straight segments meet at angled junctions. In such cases, any number of such segments can be used (in the illustrated embodiment of Fig. 3, core 2 is generally pentagonal). Regardless of the specific design (e.g. whether the core is relatively circular or oval, or exhibits relatively straight segments joined to form relatively pronounced comers, and so on), core 2 will be oriented generally concave -forward as noted above.

In some embodiments in which central core 2 exhibits relatively straight segments that meet at junctions that form relatively pronounced comers, the straps (i.e., straps 3, 3’, 4, 4’, and 5) of the harness may extend from locations at or near the junctions/comers, as is the case for the exemplary arrangements illustrated in the Figures herein. However, this does not have to be the case; any strap can extend from any location along the central core, as desired.

It is noted that a central core 2 does not have to include a continuous “floor” in order to exhibit a general bowl shape as disclosed herein. In fact, in many embodiments, core 2 it may not include a continuous floor. Thus, exemplary harness 1 as depicted in various Figures herein, depicts an arrangement in which central core 2 is not continuous; rather, a window (i.e., a through-opening) 6 is present, that is defined, and circumscribed, by central core 2.

In various embodiments, a generally bowl-shaped central core of a harness may be characterized by an average radius of curvature of the central core. Such an evaluation will be performed with the harness maintaining its central core in this shape without the need of any external support. Such a radius of curvature may be evaluated by way of a best-fit spherical dome or segment that coincides as best possible with the overall shape of the central core. If the central core exhibits a radius of curvature that varies somewhat as a function of position or orientation (e.g. when evaluated along a vertical direction versus along a horizontal direction), one or more radii may be obtained using the best fit to the shape of the core along one or more vertical segments, and one or more radii may be obtained using the best fit to the shape of the core along one or more horizontal segments, and so on. An average of these measurements can then be taken as the overall, average radius of curvature of the central core. It is acknowledged that it may not be possible to establish such a parameter with, e.g., millimeter precision. However, for the purposes herein, an average radius of curvature, can still provide a useful overall characterization even for a central core that exhibits a somewhat non-uniform bowl shape. Accordingly, in various embodiments a generally bowl-shaped central core may exhibit an average radius of curvature of at least 4, 5, 7, 9, 11, 13, or 15 cm. In further embodiments, such a central core may exhibit an average radius of curvature of at most 26, 24, 22, 20, 18, 16, 14, 12, or 10 cm. A central core 2 of harness 1 may also be characterized by way of a vertical/lateral aspect ratio that is a ratio of the maximum height to the maximum width of the central core. Such a parameter can provide a measure of whether the central core is relatively tall and narrow or short and wide. An ordinary artisan, presented with a central core, will be readily able to ascertain the appropriate height and width to use in such calculations. Such calculations may be evaluated with the harness in rear view as shown in Fig. 3. The maximum vertical height 13 of the core, and the maximum lateral width 14 of the core (as projected onto a flat plane normal to the viewing direction) are indicated on Fig. 3. In various embodiments, such an aspect ratio may be at least 0.7: 1, 1: 1, or 1.3: 1. In further embodiments, such an aspect ratio may be no greater than 2: 1, 1.7: 1, or 1.4: 1.

The providing of harness 1 with a stable, generally bowl-shaped central core 2 can be achieved by making the harness out of a compliant (e.g., relatively soft and floppy) material that is equipped with a reinforcing frame within a central portion (i.e., the portion that provides the central core of the harness) of the compliant material. The reinforcing frame will be configured so that it maintains the central core in its generally bowl-shaped condition; however, the reinforcing frame will not be so stiff that it holds the central core in a rigidly fixed configuration, as discussed in detail elsewhere herein. As shown in exemplary embodiment in Fig. 6, a reinforcing frame 50 can be embedded partially, or substantially completely, within a shell 20 of compliant material. In some convenient embodiments, a reinforcing frame 50 can be provided (e.g. by molding) and a shell 20 of compliant material can be overmolded over frame 50 as discussed in detail later herein.

By definition, the reinforcing frame 50 will be made of a material that is stiffer and harder than the compliant material 20. This property can be characterized by way of the Shore A hardness of the respective materials. Thus, the terminology of a “compliant material” and a “reinforcing frame” is defined to mean that the material of which the reinforcing frame is made will exhibit a hardness that is at least 10 Shore A hardness units higher than the Shore A hardness of the compliant material within which the reinforcing frame is embedded. In various embodiments, the reinforcing frame may exhibit a Shore A hardness that is 20, 30, 40, 50, or 60 Shore A units higher than that of the compliant material.

Within the above constraints, the absolute values of the stiffhess/hardness of these materials may be chosen as desired. In some embodiments, the reinforcing frame may be made of a material that is “semirigid” (defined here as exhibiting a Shore A hardness that is less than 90), in order that the central core of the harness can be slightly deformable rather than being rigidly fixed in its shape. A semi-rigid material is thus distinguished from rigid materials such as metals (e.g. iron or steel) and extremely rigid polymers such as various engineering polymers, glass-fiber reinforced polymers and so on. However, it is noted that other parameters (e.g. the width and/or thickness of segments of the reinforcing frame) can be manipulated to achieve the effects desired herein. That is, if a relatively stiff material is used for the reinforcing frame, the width and/or thickness of the frame may be reduced from what they might be when using a less stiff frame material. Whatever the specific configuration, a reinforcing frame 50 as disclosed herein will exhibit sufficient rigidity to stiffen the herein-described compliant material above its inherent value. A reinforcing frame, by definition, will be distinguished from any item (e.g. a fibrous web of woven, knitted or nonwoven material) that does not serve to stiffen a compliant material with which it is used.

It will be appreciated that a head harness having a central core that exhibits a stable, generally bowlshaped configuration can exhibit significant advantages over, for example, harnesses of the art that are cut from flat elastic (e.g. rubber) sheeting. Such head harnesses of the art often pull the wearer’s hair in the process of being conformed to (e.g. wrapped around) the back of the wearer’s head. In contrast, a bowlshaped central core allows the harness to be nestled snugly against the back of the wearer’s head without any need for wrapping in the manner needed with a “flat” harness. However, the fact that the bowl-shaped harness is not completely rigid (that is, it exhibits some ability to deform) means that the harness can selfadjust to the shape of a particular wearer’s head. This can be contrasted to, for example, a harness that makes use of a rigid “cage” that has little or no ability to self-adjust. Such a rigid harness might need to be provided in numerous sizes and/or shapes, whereas a harness that relies on the present arrangements may need only be provided in a small number of sizes (e.g. three, two, or even one). Still further, the fact that only a portion of the harness (i.e., the central core and, optionally, strap sections that are proximal to the central core) is reinforced in this manner, means that portions of the harness straps that are not reinforced exhibit ample ability to extend elastically as needed to fit a particular head, to bend sharply so as to be manipulable along a serpentine path through slots of a buckle, and so on. The arrangements disclosed herein thus provide significant advantages over the art in allowing a head harness to be easily and comfortably fit to wide range of head sizes and shapes.

In some embodiments, a reinforcing frame 50 may take the form of a single, integral piece of molded material (with properties as outlined above). In some embodiments, the frame may be generally ring-shaped (when viewed generally along the forward-rearward axis of the harness) as evident in Figs. 7 and 8. Generally ring-shaped does not require that frame 50 must be e.g. a perfect circle or annulus; any shape in which frame 50 defines, and surrounds, a central opening 55 is acceptable. In some embodiments, a frame 50 may take the form of a polygon in which multiple relatively straight segments (e.g. segments 51 as indicated in Figs. 7 and 8) meet at angled junctions 52. In such cases, any number of such segments can be used (in the illustrated embodiment of Figs. 7 and 8, frame 50 is generally pentagonal). Regardless of the specific design, frame 50 will be oriented generally concave-forward, so that frame 50 can help stabilize the central core 2 of the harness in the above-described configuration.

In many embodiments, the single piece of compliant material 20 may be overmolded onto frame 50, with frame 50 thus establishing the basic size and shape of central core 2 of harness 1, as is evident from Fig. 6. Frame 50 will have a forward major surface 57 and a rearward major surface 58. As shown in Fig. 8, in some embodiments at least one of these major surfaces (rearward surface 58, in Fig. 8) may have numerous (i.e., 10 or more) features 59 that enhance the bonding of the compliant material to the frame during an overmolding process. In the depicted embodiment, features 59 are all cavities (e.g. divots or depressions); however, in various embodiments, such features may be posts, a mix of cavities and posts, or any other geometric arrangement of features into which, around which, and/or between which the compliant material can flow during an overmolding process.

In some embodiments, frame 50 may be limited to a generally ring-shaped element. However, in some embodiments, frame 50 may comprise one or more reinforcing struts 53 that each extend integrally from frame 50 in a direction along a long axis of a strap of the harness and is embedded within the molded compliant material of the strap. An exemplary arrangement in which all of the straps of harness 1 (in this case, five straps) comprise such struts 53 is shown in Figs. 7 and 8. In some embodiments, any or all such struts 53 may be shaped so that they are generally congruent with the generally concave shape of the reinforcing frame 50, as is evident in Figs. 7, 8 and 9. In other words, in some embodiments the struts may extend generally along the arcuate path established by frame 50 so as to exhibit approximately the same radius of curvature as the average radius of curvature of frame 50. In many embodiments, reinforcing frame 50 and any reinforcing struts 53 that are present, are portions of a single, integral, molded piece that is made in a single molding process.

As noted, harness 1 comprises a compliant material, the central portion of which is stiffened and given a stable, generally bowl -like shape by the above-described reinforcing frame. In many convenient embodiments, the compliant material will be present in the form of a single, integral piece of molded material 20 (as evident e.g. in Fig. 7) that is overmolded onto reinforcing frame 50 so that frame 50 is at least partially embedded within compliant piece 20. As noted, in some embodiments the overmolding may be performed such that frame 50 is substantially completely embedded inside compliant piece 20 with no portion of frame 50 exposed (excepting e.g. some small portion resulting from the manner in which the frame is supported in the overmolding cavity). In other embodiments, the overmolding may be partial, so that, for example, a significant portion of the forward surface 57 of frame 50 is left exposed.

To perform the overmolding process, the compliant material can be injected into a suitably shaped mold into which previously-made frame 50 has been inserted, so that the compliant material is shaped into a form that is retained after the molding process is complete. In some embodiments (e.g. in which the compliant material is a thermoplastic material) the compliant material may be injected into the mold in molten form, after which it is cooled to solidify the material. In some embodiments (e.g. in which the compliant material is a thermoset material such as a heat-curable silicone) the compliant material may be injected into the mold in liquid form and then heated to promote crosslinking and solidification of the material.

In many embodiments, the central portion of the compliant material may be configured so that it closely matches the overall shape, and/or local features, of the reinforcing frame, as generally evident in Figs. 6 and 7. For example, each segment 51 of reinforcing frame 50 may be encapsulated within a segment 22 of compliant material 20, with the two segments co-aligned along the same axis but with the compliant material being thicker so as to forwardly and rearwardly encapsulate the frame segment 51. In some embodiments, at least some such segments 22 of compliant material may comprise flanges 21 that transversely flank the corresponding segment 51 of reinforcing frame 50, as evident in Fig. 6. That is, in such embodiments a segment 22 of compliant material 20 may be considerably transversely wider than the frame segment 51 that is encapsulated within that segment of compliant material. For example, in the exemplary depiction of Fig. 7, most of the segments 22 of compliant material 20 appear to be approximately three times as wide as the corresponding segments 51 of frame 50.

The single piece of compliant material 20 will comprise a plurality of straps that radiate from the central portion of the piece of compliant material; these straps will provide the previously-mentioned plurality of straps (e.g. straps 3, 3’, 4, 4’, and 5) of harness 1. These straps may be any suitable length. As noted earlier, in some embodiments one such strap (e.g. atop strap 5) may be arranged somewhat differently than the other straps (e.g. side straps). In the particular embodiment depicted in the Figures herein, in which the side straps are configured to pass through one or more slots of a buckle of a respirator mask, at least a portion of one or both major surfaces of the straps may comprise transversely-extending ridges 15 (as indicated in Fig. 1) that serve to increase the frictional holding power of the straps once threaded through the buckle slots. Any features that serve this purpose may be used; for example, an array of posts may be used rather than elongate ridges; or, in general, one or both surfaces of the strap may be textured in any suitable manner. The ends of the side straps may comprise features (e.g. features 31 as mentioned earlier) that enhance the ability of human fingers to grasp the end of the side straps and/or that enhance the ability of the end of the side strap to remain in place once threaded through a buckle slot. Any or all such items (e.g. ridges 15 and/or features 31) may be molded into the compliant material as part of the overmolding process.

As noted earlier, in some embodiments, one or more reinforcing struts 53 may extend from reinforcing frame 50 so as to be embedded in a strap of the harness, along a portion of the length of that strap. Any or all such harness straps (e.g. straps 3, 3’, 4, 4’, and/or 5) may thus comprise a proximal section

11 that comprises a reinforcing strut 53, and a distal section 12 that does not comprise a reinforcing strut. Typically, the distal section 12 of the strap will be much longer (e.g. 2, 3, or 4 times as long or more) than the proximal section of the strap. In other words, any such strut, if present, will have a terminal end 54 that is located far from the terminal end of the strap itself, as evident e.g. in Figs. 6 and 7.

It will be appreciated that the presence of such reinforcing struts will cause the proximal sections of the harness straps to exhibit a relatively stable shape that may be generally congruent with the shape of the central core of the harness, again as evident in Figs. 6 and 7. However, the distal portions of the harness straps, lacking any such strut, will be significantly more pliable and/or stretchable, so that the straps can be easily manipulated in the act of securing the straps to the buckles of a respirator mask. In this regard it is noted that in various Figures herein (e.g. Figs. 6 and 7), pronounced bends are depicted in the distal portions

12 of the straps of the harness at locations just beyond the ends 54 of struts 53. These bends were included in the Figures so that the harness straps could more easily be shown in a fully extended condition. These Figures are not to be taken as indicating that the depicted bends in the harness straps are permanent and/or are maintained in place by the frame or struts. In fact, from the disclosures herein it will be appreciated that these bends can be easily straightened, and that any section of the distal portions of the harness straps can be bent in similar manner to that shown in these Figures, at any location along the entire length of the distal portions.

As noted, the herein-disclosed head harness 1 can be produced e.g. by overmolding a compliant injection-moldable material onto a generally ring-shaped, concave reinforcing frame so that the compliant material forms a single, integral piece with a generally bowl-shaped central portion and a plurality of straps radiating from the central portion, and so that the generally ring-shaped, concave, molded reinforcing frame is at least partially embedded within the central portion of the single, integral piece of compliant material. The overmolding can be performed by placing a reinforcing frame (premade by any suitable method, with injection molding being particularly convenient) into a molding cavity into which the compliant material, in flowable form, is injected so as to at least partially encapsulate the reinforcing frame (and reinforcing struts, if present).

In some embodiments the reinforcing frame is the only item that is overmolded by the compliant material. However, in some embodiments, the overmolding can be a two-item overmolding process in which the reinforcing frame 50 and the previously described top clip 36 are both overmolded by the compliant material. As shown in detail in the magnified isolated exploded view of Fig. 10, the terminal end section 32 of top strap 5 may be overmolded around a bonding section 37 of top clip 36, to permanently bond the top clip 36 to the terminal end 32 of top strap 5. The bonding section 37 may include features (e.g. cavities and/or serrated teeth, both of which are visible in Fig. 10) to enhance the bonding that is achieved by the overmolding process. The actual portion of top clip 36 that will mate with a buckle of a strap of a respirator mask will remain exposed rather than substantially the entirety of top clip 36 being encapsulated within the compliant material. The overmolding of top clip 36 is thus a partial overmolding rather than a full overmolding.

Also shown in Fig. 10 is a magnified view of previously-mentioned fastener 103 that can be provided on a top strap 102 of a respirator mask. The depicted fastener 103 is complementary to, and can be mated with, top clip 36. As noted, the other straps of the depicted harness 1 (and corresponding buckles of the respirator mask) are configured for threading/frictional retention. However, if desired, any such set of straps and buckles can be configured in similar manner to the top strap, e.g. with an overmolded clip that is configured to mate with a complementary fastener or buckle. Further details of the particular style of fastener 103 shown in Fig. 10 (and details of respirator masks of the general type shown in Fig. 4) can be found in U.S. Patent Application Publication No. 2019/0118009, which is incorporated by reference in its entirety for this purpose. Any suitable material may be used as the compliant material. Such material may be moldable, whether a thermoplastic material or a thermoset material. Potentially suitable materials include e.g. silicone rubber, natural rubber, SBR rubber, EPDM rubber, chloroprene rubber, neoprene rubber, and so on. Likewise, any suitable material may be used to form the reinforcing frame. For example, an injection- moldable organic polymeric material may be used. In some embodiments, such a material may be a thermoplastic elastomer. Although some thermoplastic elastomers are available that are extremely soft, in the present instance it is required that any such thermoplastic elastomer that is used to form a reinforcing frame will have to exhibit a hardness that is higher than that of the compliant material with which the frame is used, as discussed earlier herein. Again, it is emphasized that for the purposes herein, it is not desirable to render the harness (in particular, the central core of the harness) extremely rigid; rather, the goal is to impart the central core with a three-dimensional concave shape that is self-supporting (e.g. so that the harness will not collapse flat under its own weight) but that nevertheless is somewhat conformable so as to adjust to the particular shape of a wearer’s head. Potentially suitable materials to use for the frame include thermoplastic elastomers based on block copolymers (e.g. HYTREL, KRATON, PEBAX, and the like), polyurethanes (e.g. SANTOPRENE), and so on.

In some embodiments, the compliant material and the reinforcing frame need not necessarily be made of materials that differ substantially in chemical composition. For example, the materials may be of similar composition, but may differ in e.g. molecular weight, amount and type of hard segments (e.g. if the materials are block copolymers), degree of crosslinking (e.g. if the materials are networked thermosets), and so on. Any polymeric material that is used may comprise a suitable type and amount of additive(s), e.g. a reinforcing mineral filler, to purposefully tailor the physical properties, e.g. stiffness, of the material. Still further, if the head harness is to meet any particular temperature requirements, the compliant material and/or the reinforcing frame may be made of materials chosen in view of such considerations.

It will be appreciated that many variations of the above-discussed arrangements are possible. For example, although the various segments (and struts) of the reinforcing frame 50 as depicted in the Figures herein are rather uniform in width and thickness, this does not have to be the case. For example, one or more segments could have a portion in which the width is narrowed, the thickness is reduced, or both. (In an extreme case, a segment could have a discontinuity.) Any such arrangement can reduce the local stiffness of that segment of the harness if this is desired.

The arrangement and features of the piece of compliant material 20 can also be varied. For example, although the Figures herein depict compliant piece 20 as defining a central opening 25 (with opening 25 combining with opening 55 of reinforcing frame 50 to provide window 6 of harness 1), in some embodiments at least a portion of compliant piece 20 may partially, or completely, extend across the space between various segments of compliant piece 20 so that opening 25 is subdivided into smaller portions or is even absent. In some embodiments a portion, or the entirety, of window 6 and/or central core 2 of harness 1 may be fitted e.g. with a fabric cover or shield. The herein-disclosed head harness may be used in combination with any suitable respirator mask. While most such respirator masks are so-called full face masks (of the general type shown in Fig. 4), the herein-disclosed harness may be used with any type or style of respirator mask, for example a so-called half-mask respirator. The herein-disclosed head harness may bear a superficial resemblance to some so- called head suspensions that are used in combination with various helmets, e.g. welding helmets. Such head suspensions rest on the uppermost part of the head and are used to support the weight of a helmet atop the head. In contrast, the herein-disclosed head harness is used to securely hold a respirator mask to the face and to support the weight of the respirator mask in that position. The herein-described head harness is thus configured to have a central core that is seated against the rear surface of the wearer’s head (i.e., against the lower portion of the parietal bone and/or the upper portion of the occipital bone). A head harness as disclosed herein thus differs from a head suspension and addresses a different set of problems than a head suspension.

It will be apparent to those skilled in the art that the specific exemplary embodiments, elements, structures, features, details, arrangements, configurations, etc., that are disclosed herein can be modified and/or combined in numerous ways. In summary, numerous variations and combinations are contemplated as being within the bounds of the conceived invention, not merely those representative designs that were chosen to serve as exemplary illustrations. Thus, the scope of the present invention should not be limited to the specific illustrative structures described herein, but rather extends at least to the structures described by the language of the claims, and the equivalents of those structures. Any of the elements that are positively recited in this specification as alternatives may be explicitly included in the claims or excluded from the claims, in any combination as desired. Any of the elements or combinations of elements that are recited in this specification in open-ended language (e.g., comprise and derivatives thereof), are considered to additionally be recited in closed-ended language (e.g., consist and derivatives thereof) and in partially closed-ended language (e.g., consist essentially, and derivatives thereof). Although various theories and possible mechanisms may have been discussed herein, in no event should such discussions serve to limit the claimable subject matter. To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document that is incorporated by reference herein but to which no priority is claimed, this specification as written will control.