Horizontal flat-fold filtering face-piece respirator having indicia of symmetry

Abstract

A horizontal flat-fold, filtering face-piece respirator 10 that includes a harness 14 and a mask body 12 that has a front surface, a first perimeter 24a, and a longitudinal axis 34. A nose clip 30 is secured to the mask body 12 centrally and adjacent to the first perimeter 24a of the mask body 12. An indicia 32 that is visible on the front surface of the mask body 12 in a vicinity of the nose clip 30 is provided to highlight a longitudinal axis of symmetry of the nose clip. The use of such an indicia, visible from the mask body front surface, enables a user to readily identify where the nose clip may be bent to prepare it for donning by the wearer.

Claims

1. A horizontal flat-fold, filtering face-piece respirator that comprises: a harness; a mask body that has a front surface, a first perimeter, a series of bonds or welds located along the first perimeter, and a longitudinal axis; a nose clip that is secured to the mask body centrally and adjacent the first perimeter of the mask body; and an indicia that is distinguishable from the series of bonds or welds and that is visible on the front surface of the mask body adjacent the first perimeter and the nose clip at the longitudinal axis of the mask body, wherein the indicia is printed on an outer surface of the mask body, wherein the indicia comprises a printed line located at the longitudinal axis of the mask body, and further wherein the indicia indicates a longitudinal axis of symmetry of the nose clip.

2. The respirator of claim 1, wherein the indicia is printed on a cover web under which the nose clip is located.

3. The respirator of claim 1, wherein the printed line is about 1 to 4 mm wide and 2 to 8 mm long.

4. The respirator of claim 1, wherein the mask body comprises a filter media and one or more cover webs, at least one of the cover webs residing over the nose clip but still allowing the nose clip to be visible thereunder.

5. The respirator of claim 1, further comprising indicia integral to the nose clip.

6. The respirator of claim 1, wherein the nose clip is linear when the respirator is in a horizontally folded condition.

7. A horizontal flat-fold, filtering face-piece respirator that comprises: a harness; a mask body that has a front surface, a first perimeter, a series of bonds or welds located along the first perimeter, and a longitudinal axis; a nose clip that is secured to the mask body centrally and adjacent the first perimeter of the mask body; and an indicia that is distinguishable from the series of bonds or welds and that is visible on the front surface of the mask body adjacent the first perimeter at the longitudinal axis of the mask body, wherein the indicia is integral to the nose clip, wherein the indicia comprises a weakened area comprising at least one of a notch, a score line, and a small circular opening in the nose clip.

8. The respirator of claim 7, wherein the nose clip is disposed on an outer most layer of a filtering structure of the mask body.

9. The respirator of claim 7, wherein the mask body comprises a filtering structure comprising an inner cover web, an outer cover web, and a filtration layer between the inner and outer cover webs, wherein the nose clip is disposed between the outer cover web and the filtration layer.

10. The respirator of claim 7, wherein the indicia comprises the notch in the nose clip and printed indicia on the nose clip.

11. The respirator of claim 7, wherein the indicia comprises a v-shaped notch.

12. The respirator of claim 7, wherein the indicia comprises the notch and the score line.

13. The respirator of claim 7, wherein the nose clip is linear when the respirator is in a horizontally folded condition.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a front perspective view of a horizontal flat-fold filtering face-piece respirator 10, in accordance with the present invention, being worn on a person's face;

(2) FIG. 2 is a top view of the respirator 10 of FIG. 1 in a horizontally folded condition;

(3) FIG. 3 is a top view of a nose clip 30′ that may be used in connection with the present invention;

(4) FIG. 4 is a cross-sectional view of the mask body 12 taken along lines 4-4 of FIG. 2; and

(5) FIG. 5 is a cross-sectional view of the filtering structure 16 taken along lines 5-5 of FIG. 4.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(6) In practicing the present invention, a horizontal flat-fold, filtering face-piece respirator is provided that has a visual and/or mechanical feature (indicia) that allows the user to easily locate the centerline of the nose clip on an expandable face mask so the nose clip can be “pre-conformed” by the user into a general “v” or “u” shape before donning. This pre-bend in the nose clip helps hold the mask body in a three-dimension shape that makes donning of the mask easier and more symmetrically accurate. Another aspect of the invention is a feature on the nose clip or mask body that entices the flat-folded mask to be symmetrically opened. This feature could be, for instance, two plastic pieces that straddle the longitudinal axis 34 with a gap such that a “living hinge” is created—enticing the mask body 12 to open in a symmetrical fashion. Another possibility is that the nose clip has a notch, score, line, hole or other feature centrally located on the nose clip, such that it is weaker in this area. When the mask body is opened—the nose clip has a tendency to fold in this weakened area, which is centrally located on the nose clip, enticing the mask body to be symmetrically opened.

(7) FIG. 1 shows an example of a horizontal flat-fold filtering face-piece respirator 10 in an opened condition on a wearer's face. The respirator 10 may be used in accordance with the present invention to provide clean air for the wearer to breathe. As illustrated, the filtering face-piece respirator 10 includes a mask body 12 and a harness 14. The mask body 12 has a filtering structure 16 through which inhaled air must pass before entering the wearer's respiratory system. The filtering structure 16 removes contaminants from the ambient environment so that the wearer can breathe clean air. The mask body 12 includes a top portion 18 and a bottom portion 20. The top portion 18 and the bottom portion 20 are separated by a line of demarcation 22. In this particular embodiment, the line of demarcation 22 may be a pleat or fold line that extends transversely across the central portion of the mask body. The mask body 12 also includes a perimeter that includes an upper segment 24a and a lower segment 24b. The harness 14 has a strap 26 that is stapled to a tab 28a. A nose clip 30 may be placed on the top portion 18 of the mask body on an outer surface or beneath a cover web adjacent to the upper segment 24a. An indicia 32 may be visible on the front surface of the mask body 12 adjacent to the nose clip 30.

(8) FIG. 2 illustrates that the indicia 32 can be located at the longitudinal axis 34 of the mask body 12. The indicia may be a printed line that is about 1 to 4 millimeters (mm) wide and about 2 to 8 mm long. The face-contacting periphery of the mask body 12 generally resides within the bracketed area 36. The mask body perimeter may have a series of bonds or welds 37 to join the various layer of the mask body 12 together. The mask body 12 also may include a pleat line 38 that extends from a first side to a second side of the mask body, transversely. On each side of the mask body 12 are tabs 28a, 28b that provide a surface for grasping the mask body 12 during donning, adjusting, and doffing. An indicator 39a, 39b, resembling a fingerprint, can be provided on each tab to highlight where the user may grasp the mask body 12. The use of the grasping indicator is further described in U.S. patent application Ser. No. 12/562,273, entitled Filtering Face-Piece Respirator Having Grasping Feature Indicator, filed Sep. 18, 2009.

(9) FIG. 3 illustrates an example of a nose clip 30′ that may have the indicia as an integral part of the nose clip itself. The nose clip 30′ has a small notch 40 cut into the first edge 42 of the nose clip 30′. As illustrated, the notch 40 resembles the shape of a “v”. The notch, of course, could take on other configurations such as being u-shaped, rectangular-shaped, or hemispherical. For manufacturing purposes, each nose clip could have an indent notch and a corresponding out-dent notch. Additionally, if the nose clip 30′ has sufficient thickness, the center of the nose clip could be identified by a small circular opening stamped at the bisecting line of symmetry of the nose clip 30′. When the indicia is integral to the nose clip as illustrated in FIG. 3, the nose clip, preferably, is disposed on the outer most layer of the filtering structure 16. If the nose clip is capable of being viewed beneath a sufficiently thin outer layer of cover web, the nose clip could be placed beneath it as illustrated in, for example, FIGS. 1 and 4. In addition to a notch 40, a score line or other indicia could be placed on the nose clip.

(10) FIG. 4 illustrates an example of a pleated configuration of a horizontal flat-fold mask body 12 that may be used in the present invention. As shown, the mask body 12 includes pleats 22 and 38, already described with reference to FIGS. 1 and 2. The upper portion or panel 18 of the mask body 12 also includes pleat 44. The lower portion or panel 20 of the mask body 12 includes pleats 46, 48, 50, 52, and 54. The lower portion 20 of the mask body 12 may include more filter media surface area than the upper portion 18. The mask body 12 also includes a perimeter web 57 that is secured to the mask body along its perimeter. The perimeter web 57 may be folded over the mask body at the perimeter 24a, 24b. The perimeter web 57 also may be an extension of an inner cover web 58 folded and secured around the edge of 24a and 24b. The nose clip 30 may be disposed on the upper portion 18 of the mask body centrally adjacent to the perimeter between the filtering structure 16 and the perimeter web 57. The nose clip 30 may be made from a pliable dead soft metal or plastic that is capable of being manually adapted by the wearer to fit the contour of the wearer's nose. The nose clip may be made from aluminum and may be linear as shown in FIGS. 2 and 3 or it may take on other shapes when viewed from the top such as the m-shaped nose clip shown in U.S. Pat. No. 5,558,089 and Des. 412,573 to Castiglione. A plastic nose clip is described in published U.S. Patent Application Publication 2007/0068529A1 to Kalatoor. As shown, the upper portion 18 appears as a pleated panel when the mask body 12 is in a folded condition; similarly the lower portion 20 (FIG. 1) appears as a pleated panel when the mask is in its folded storage condition.

(11) FIG. 5 illustrates that the filtering structure 16 may include one or more layers of fibrous material, such as the inner cover web 58, an outer cover web 60, and a filtration layer 62. The inner and outer cover webs 58 and 60 may be provided to protect the filtration layer 62 and to preclude fibers from the filtration layer 62 from coming loose and entering the mask interior. During respirator use, air passes sequentially through layers 60, 62, and 58 before entering the mask interior. The air that is disposed within the interior gas space of the mask may then be inhaled by the wearer. When a wearer exhales, the air passes in the opposite direction sequentially through layers 58, 62, and 60. Alternatively, an exhalation valve (not shown) may be provided on the mask body to allow exhaled air to be rapidly purged from the interior gas space to enter the exterior gas space without passing through filtering structure 16. Typically, the cover webs 58 and 60 are made from a selection of nonwoven materials that provide a comfortable feel, particularly on the side of the filtering structure that makes contact with the wearer's face. The construction of various filter layers and cover webs that may be used in conjunction with the support structure of the present invention are described below in more detail. To improve wearer fit and comfort, an elastomeric face seal can be secured to the perimeter of the filtering structure 16. Such a face seal may extend radially inward to contact the wearer's face when the respirator is being donned. Examples of face seals are described in U.S. Pat. No. 6,568,392 to Bostock et al., U.S. Pat. No. 5,617,849 to Springett et al., and U.S. Pat. No. 4,600,002 to Maryyanek et al., and in Canadian Patent 1,296,487 to Yard. The filtering structure also may have a structural netting or mesh juxtaposed against at least one or more of the layers 58, 60, or 62, typically against the outer surface of the outer cover web 60. The use of such a mesh is described in U.S. Patent Publication 2010/0154806 A1 to Duffy.

(12) The horizontal mask body that is used in connection with the present invention may take on a variety of different shapes and configurations. Generally the shape and configuration of the filtering structure corresponds to the general shape of the mask body. Although a filtering structure has been illustrated with multiple layers that include a filtration layer and two cover webs, the filtering structure may simply comprise a filtration layer or a combination of filtration layers. For example, a pre-filter may be disposed upstream to a more refined and selective downstream filtration layer. Additionally, sorptive materials such as activated carbon may be disposed between the fibers and/or various layers that comprise the filtering structure. Further, separate particulate filtration layers may be used in conjunction with sorptive layers to provide filtration for both particulates and vapors. The filtering structure may include one or more stiffening layers that assist in providing a cup-shaped configuration. The filtering structure also could have one or more horizontal and/or vertical lines of demarcation that contribute to its structural integrity. Using the first and second flanges in accordance with the present invention, however, may make unnecessary the need for such stiffening layers and lines of demarcation.

(13) The filtering structure that is used in a mask body of the invention can be of a particle capture or gas and vapor type filter. The filtering structure also may be a barrier layer that prevents the transfer of liquid from one side of the filter layer to another to prevent, for instance, liquid aerosols or liquid splashes (e.g. blood) from penetrating the filter layer. Multiple layers of similar or dissimilar filter media may be used to construct the filtering structure of the invention as the application requires. Filters that may be beneficially employed in a layered mask body of the invention are generally low in pressure drop (for example, less than about 195 to 295 Pascals at a face velocity of 13.8 centimeters per second) to minimize the breathing work of the mask wearer. Filtration layers additionally are flexible and have sufficient shear strength so that they generally retain their structure under the expected use conditions. Examples of particle capture filters include one or more webs of fine inorganic fibers (such as fiberglass) or polymeric synthetic fibers. Synthetic fiber webs may include electret-charged polymeric microfibers that are produced from processes such as meltblowing. Polyolefin microfibers formed from polypropylene that has been electrically charged provide particular utility for particulate capture applications. As alternate filter layer may comprise a sorbent component for removing hazardous or odorous gases from the breathing air. Sorbents may include powders or granules that are bound in a filter layer by adhesives, binders, or fibrous structures—see U.S. Pat. No. 6,234,171 to Springett et al. and U.S. Pat. No. 3,971,373 to Braun. A sorbent layer can be formed by coating a substrate, such as fibrous or reticulated foam, to form a thin coherent layer. Sorbent materials may include activated carbons that are chemically treated or not, porous alumna-silica catalyst substrates, and alumna particles. An example of a sorptive filtration structure that may be conformed into various configurations is described in U.S. Pat. No. 6,391,429 to Senkus et al.

(14) The filtration layer is typically chosen to achieve a desired filtering effect. The filtration layer generally will remove a high percentage of particles and/or or other contaminants from the gaseous stream that passes through it. For fibrous filter layers, the fibers selected depend upon the kind of substance to be filtered and, typically, are chosen so that they do not become bonded together during the molding operation. As indicated, the filtration layer may come in a variety of shapes and forms and typically has a thickness of about 0.2 millimeters (mm) to 1 centimeter (cm), more typically about 0.3 mm to 0.5 cm, and it could be a generally planar web or it could be corrugated to provide an expanded surface area—see, for example, U.S. Pat. Nos. 5,804,295 and 5,656,368 to Braun et al. The filtration layer also may include multiple filtration layers joined together by an adhesive or any other means. Essentially any suitable material that is known (or later developed) for forming a filtering layer may be used as the filtering material. Webs of melt-blown fibers, such as those taught in Wente, Van A., Superfine Thermoplastic Fibers, 48 Indus. Engn. Chem., 1342 et seq. (1956), especially when in a persistent electrically charged (electret) form are especially useful (see, for example, U.S. Pat. No. 4,215,682 to Kubik et al.). These melt-blown fibers may be microfibers that have an effective fiber diameter less than about 20 micrometers (μm) (referred to as BMF for “blown microfiber”), typically about 1 to 12 μm. Effective fiber diameter may be determined according to Davies, C. N., The Separation Of Airborne Dust Particles, Institution Of Mechanical Engineers, London, Proceedings 1B, 1952. Particularly preferred are BMF webs that contain fibers formed from polypropylene, poly(4-methyl-1-pentene), and combinations thereof. Electrically charged fibrillated-film fibers as taught in van Turnhout, U.S. patent Re. 31,285, also may be suitable, as well as rosin-wool fibrous webs and webs of glass fibers or solution-blown, or electrostatically sprayed fibers, especially in microfilm form. Electric charge can be imparted to the fibers by contacting the fibers with water as disclosed in U.S. Pat. No. 6,824,718 to Eitzman et al., U.S. Pat. No. 6,783,574 to Angadjivand et al., U.S. Pat. No. 6,743,464 to Insley et al., U.S. Pat. Nos. 6,454,986 and 6,406,657 to Eitzman et al., and U.S. Pat. Nos. 6,375,886 and 5,496,507 to Angadjivand et al. Electric charge also may be imparted to the fibers by corona charging as disclosed in U.S. Pat. No. 4,588,537 to Klasse et al. or by tribocharging as disclosed in U.S. Pat. No. 4,798,850 to Brown. Also, additives can be included in the fibers to enhance the filtration performance of webs produced through the hydro-charging process (see U.S. Pat. No. 5,908,598 to Rousseau et al.). Fluorine atoms, in particular, can be disposed at the surface of the fibers in the filter layer to improve filtration performance in an oily mist environment—see U.S. Pat. Nos. 6,398,847 B1, 6,397,458 B1, and 6,409,806 B1 to Jones et al. Typical basis weights for electret BMF filtration layers are about 10 to 100 grams per square meter. When electrically charged according to techniques described in, for example, the '507 Angadjivand et al. patent, and when including fluorine atoms as mentioned in the Jones et al. patents, the basis weight may be about 20 to 40 g/m.sup.2 and about 10 to 30 g/m.sup.2, respectively.

(15) An inner cover web can be used to provide a smooth surface for contacting the wearer's face, and an outer cover web can be used to entrap loose fibers in the mask body or for aesthetic reasons. The cover web typically does not provide any substantial filtering benefits to the filtering structure, although it can act as a pre-filter when disposed on the exterior (or upstream to) the filtration layer. To obtain a suitable degree of comfort, an inner cover web preferably has a comparatively low basis weight and is formed from comparatively fine fibers. More particularly, the cover web may be fashioned to have a basis weight of about 5 to 50 g/m.sup.2 (typically 10 to 30 g/m.sup.2), and the fibers may be less than 3.5 denier (typically less than 2 denier, and more typically less than 1 denier but greater than 0.1). Fibers used in the cover web often have an average fiber diameter of about 5 to 24 micrometers, typically of about 7 to 18 micrometers, and more typically of about 8 to 12 micrometers. The cover web material may have a degree of elasticity (typically, but not necessarily, 100 to 200% at break) and may be plastically deformable.

(16) Suitable materials for the cover web may be blown microfiber (BMF) materials, particularly polyolefin BMF materials, for example polypropylene BMF materials (including polypropylene blends and also blends of polypropylene and polyethylene). A suitable process for producing BMF materials for a cover web is described in U.S. Pat. No. 4,013,816 to Sabee et al. The web may be formed by collecting the fibers on a smooth surface, typically a smooth-surfaced drum or a rotating collector—see U.S. Pat. No. 6,492,286 to Berrigan et al. Spun-bond fibers also may be used.

(17) A typical cover web may be made from polypropylene or a polypropylene/polyolefin blend that contains 50 weight percent or more polypropylene. These materials have been found to offer high degrees of softness and comfort to the wearer and also, when the filter material is a polypropylene BMF material, to remain secured to the filter material without requiring an adhesive between the layers. Polyolefin materials that are suitable for use in a cover web may include, for example, a single polypropylene, blends of two polypropylenes, and blends of polypropylene and polyethylene, blends of polypropylene and poly(4-methyl-1-pentene), and/or blends of polypropylene and polybutylene. One example of a fiber for the cover web is a polypropylene BMF made from the polypropylene resin “Escorene 3505G” from Exxon Corporation, providing a basis weight of about 25 g/m.sup.2 and having a fiber denier in the range 0.2 to 3.1 (with an average, measured over 100 fibers of about 0.8). Another suitable fiber is a polypropylene/polyethylene BMF (produced from a mixture comprising 85 percent of the resin “Escorene 3505G” and 15 percent of the ethylene/alpha-olefin copolymer “Exact 4023” also from Exxon Corporation) providing a basis weight of about 25 g/m.sup.2 and having an average fiber denier of about 0.8. Suitable spunbond materials are available, under the trade designations “Corosoft Plus 20”, “Corosoft Classic 20” and “Corovin PP-S-14”, from Corovin GmbH of Peine, Germany, and a carded polypropylene/viscose material available, under the trade designation “370/15”, from J. W. Suominen OY of Nakila, Finland.

(18) Cover webs that are used in the invention preferably have very few fibers protruding from the web surface after processing and therefore have a smooth outer surface. Examples of cover webs that may be used in the present invention are disclosed, for example, in U.S. Pat. No. 6,041,782 to Angadjivand, U.S. Pat. No. 6,123,077 to Bostock et al., and WO 96/28216A to Bostock et al.

(19) The strap(s) that are used in the harness may be made from a variety of materials, such as thermoset rubbers, thermoplastic elastomers, braided or knitted yarn/rubber combinations, inelastic braided components, and the like. The strap(s) may be made from an elastic material such as an elastic braided material. The strap preferably can be expanded to greater than twice its total length and be returned to its relaxed state. The strap also could possibly be increased to three or four times its relaxed state length and can be returned to its original condition without any damage thereto when the tensile forces are removed. The elastic limit thus is preferably not less than two, three, or four times the length of the strap when in its relaxed state. Typically, the strap(s) are about 20 to 30 cm long, 3 to 10 mm wide, and about 0.9 to 1.5 mm thick. The strap(s) may extend from the first tab to the second tab as a continuous strap or the strap may have a plurality of parts, which can be joined together by further fasteners or buckles. For example, the strap may have first and second parts that are joined together by a fastener that can be quickly uncoupled by the wearer when removing the mask body from the face. An example of a strap that may be used in connection with the present invention is shown in U.S. Pat. No. 6,332,465 to Xue et al. Examples of fastening or clasping mechanism that may be used to joint one or more parts of the strap together is shown, for example, in the following U.S. Pat. No. 6,062,221 to Brostrom et al., U.S. Pat. No. 5,237,986 to Seppala, and EP1,495,785A1 to Chien.

(20) As indicated, an exhalation valve may be attached to the mask body to facilitate purging exhaled air from the interior gas space. The use of an exhalation valve may improve wearer comfort by rapidly removing the warm moist exhaled air from the mask interior. See, for example, U.S. Pat. Nos. 7,188,622, 7,028,689, and 7,013,895 to Martin et al.; U.S. Pat. Nos. 7,428,903, 7,311,104, 7,117,868, 6,854,463, 6,843,248, and 5,325,892 to Japuntich et al.; U.S. Pat. No. 6,883,518 to Mittelstadt et al.; and U.S. patent RE37,974 to Bowers. Essentially any exhalation valve that provides a suitable pressure drop and that can be properly secured to the mask body may be used in connection with the present invention to rapidly deliver exhaled air from the interior gas space to the exterior gas space.

(21) This invention may take on various modifications and alterations without departing from its spirit and scope. Accordingly, this invention is not limited to the above-described but is to be controlled by the limitations set forth in the following claims and any equivalents thereof.

(22) This invention also may be suitably practiced in the absence of any element not specifically disclosed herein.

(23) All patents and patent applications cited above, including those in the Background section, are incorporated by reference into this document in total. To the extent there is a conflict or discrepancy between the disclosure in such incorporated document and the above specification, the above specification will control.