BACKGROUND OF THE INVENTION
Embodiments of the present invention relate to face masks and, more particularly, to high speed automated production of face masks.
BRIEF STATEMENT OF THE INVENTION
Embodiments of the present invention are directed to systems, apparatus, and methods for making a face mask. More specifically, embodiments of the present invention are directed to a method for making a face mask through high speed automated production, a system for practicing the method, and a product made by the method.
In accordance with one aspect of the invention, a method of manufacturing a face mask includes coupling at least one tensioned elastic structure to at least one web material to form a continuous elastic strap, advancing the continuous elastic strap in a machine direction, coupling the continuous elastic strap to a multi-layer mask web traveling in the machine direction to form a continuous face mask composite structure, the multi-layer mask web comprising an inner web layer, an outer web layer, and a filter layer positioned therebetween, and cutting the continuous face mask composite structure to define a plurality of discrete face masks.
In accordance with another aspect of the invention, a face mask includes a multi-layer mask panel comprising an inner web layer, an outer web layer, and at least one filter layer positioned therebetween and at least one elastic strap coupled to the multi-layer mask web, the at least one elastic strap comprising at least one elastic structure coupled between a first web layer and a second web layer.
In accordance with another aspect of the invention, an apparatus for manufacturing a plurality of face masks includes at least one strap bonding unit configured to couple at least one tensioned elastic structure to at least one web material to form a continuous elastic strap and a feeding unit configured to advance the continuous elastic strap in a machine direction. The apparatus also includes a mask bonding unit configured to couple the continuous elastic strap to a multi-layer mask web traveling in the machine direction to form a continuous face mask composite structure, the multi-layer mask web comprising an inner web layer, an outer web layer, and a filter layer positioned therebetween. The apparatus further includes a cutting unit configured to cut the continuous face mask composite structure to define a plurality of discrete face masks.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate embodiments presently contemplated for carrying out the invention.
In the drawings:
FIG. 1 is a schematic view of a portion of the manufacturing line for forming face masks according to an embodiment of the invention.
FIGS. 1A and 1B are schematic views of portions of the manufacturing line of FIG. 1 according to alternative embodiments of the invention.
FIG. 2 is a flowchart illustrating a method for making a face mask according to an embodiment of the invention.
FIGS. 3-9 are systematic diagrams illustrating the multi-layer mask web of FIG. 1 during the manufacturing process according to embodiments of the invention.
FIG. 10 is a schematic view of an individual face mask unit producible via the manufacturing line and method of FIGS. 1 and 2 according to an embodiment of the invention.
FIG. 11-14 are side plan views of an individual face mask unit producible via the manufacturing line and method of FIGS. 1 and 2 according to embodiments of the invention.
FIG. 15 is a schematic diagram of an elasticized strap web with deactivation zones according to an embodiment of the invention.
DETAILED DESCRIPTION
Embodiments of the present invention provide for a system and method for high speed automated production of face masks.
Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other specific structures. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
As illustrated in FIG. 1, a schematic view of a portion of a manufacturing line 100 for forming face masks according to an embodiment of the invention is shown. FIG. 2 illustrates a flowchart illustrating a method 200 for making face masks according to an embodiment of the invention. Referring to both FIGS. 1 and 2, a plurality of bendable strips 102 is supplied (step 202 of FIG. 2) from a supply spool 104 of bendable material such as metal. Each bendable strip 102 may be cut or otherwise separated from the supply spool 104 by a separator unit 106 such as a slip cut unit or other type of spacing and cutting unit. In an alternative embodiment where bendable strips 102 are provided in discrete form, the separator unit 106 may be omitted.
The bendable strips 102 are provided to a multi-layer mask web 108 that includes an outer layer 110, a filter layer 112, and an inner layer 114 stacked together (step 204 of FIG. 2). As non-limiting examples, outer and inner layers 110, 114 may include nonwoven materials, woven materials, films, foams, and/or composites or laminates of any of these material types. In the embodiment illustrated in FIG. 1, the outer and inner layers 110, 114 are separate webs. However, embodiments of the invention contemplate that the outer and inner layers 110, 114 may be formed from a single web folded about the filter layer 112. In addition, the filter layer 112 may include single or multiple layers of filter material that may be flat or may have folds or pleats formed therein. The bendable strips 102 may be positioned between the outer layer 110 and filter layer 112 (as illustrated in FIG. 1), between the filter layer 112 and inner layer 114, between multiple filter layers 112, or to the outward-facing surface of inner layer 114. An adhesive may be optionally applied from an adhesive applicator 116 directly to each bendable strip 102 or to one of the layers to which it is being supplied.
As illustrated, the multi-layer mask web 108 includes the outer layer 110, the filter layer 112, and the inner layer 114. Optional materials such as foam or other types of padding 118 may be included adjacent to bendable strip 102 either externally (as shown; step 206 of FIG. 2) or internally to increase the comfort of the wearer of the mask.
In one embodiment, the outer layer 110 may be wider than the inner layer 114 such that one or both of the longitudinal edges 122, 124 of the outer layer 110 extend beyond the longitudinal edges 126, 128 of the inner layer 114. Alternatively, one or both of the longitudinal edges 126, 128 of the inner layer 114 may be wider than the corresponding edges 122, 124 of the outer layer 110. Accordingly, an optional edge folder 120 may fold the extending longitudinal edges 122-128 to overlap the longitudinal edges 122-128 of the opposite layer (step 208 of FIG. 2).
The multi-layer mask web 108 is provided to an edge sealer 130 so that the outer and inner layers 110, 114 may be joined or sealed together (step 210 of FIG. 2). In a preferred embodiment, the sealing of the outer and inner layers 110, 114 locks the filter layer 112 between the outer and inner layers 110, 114 so that its position remains fixed. Alternatively, the position of the filter layer 112 may be fixed through other methods such as adhesive.
In one embodiment, the outer and inner layers 110, 114 are joined or sealed together using a bonding apparatus using any known ultrasonic welding system in alternative embodiments, including, as non-limiting examples, a rotary ultrasonic welding system or a blade ultrasonic welding system. For example, a rotary anvil and an ultrasonic fixed blade horn, also known as a sonotrode, cooperate with each other to bond the outer and inner layers 110, 114. Alternative embodiments may include multiple fixed blade horns or one or more rotary horns.
The ultrasonic emission of energy from the edge sealer 130 is concentrated at specific bond points where frictional heat fuses the layers of web together without the need for consumable adhesives. While the edge sealer 130 may include an ultrasonic bonding assembly that ultrasonically fuses layers of web together as described herein, it is contemplated that the techniques described herein may be extended to any other known welding or bonding techniques that fuse together two or more material layers including ultrasonic, thermal, or pressure bonding techniques and various other forms of welding known in the industry.
Alternatively, the edge sealer 130 may include an adhesive applicator and one or more rollers configured to apply adhesive or glue between the outer and inner layers 110, 114 and to apply pressure thereto to join the outer and inner layers 110, 114 together.
Alternatively, the edge sealer 130 may include a thermal bonding unit (not shown) configured to heat one or both of the outer and inner layers 110, 114 and press the layers 110, 114 together causing the outer and inner layers 110, 114 to be joined together.
It may be desirous to have the speed or feed rate of the multi-layer mask web 108 changed to a slower speed in locations where bonding or sealing of the outer and inner layers 110, 114 is to occur. In this case, a system configured to selectively decrease the feed rate of the mask web 108 at the bond location may be used, such as, for example, multiple festoon accumulators may be used to slow the web to a bonding velocity in a manner disclosed in U.S. Pat. No. 10,537,479, issued to Curt G. Joa, Inc. of Sheboygan Falls, Wis. and which is incorporated herein by reference in its entirety.
In an embodiment where it is desirable to remove one or more portions of the longitudinal edges 122-128 extending beyond bond joints between the outer and inner layers 110, 114, an optional trimmer 132 may slit the multi-layer mask web 108 to separate undesirable portions therefrom to be discarded (step 212 of FIG. 2).
Downstream of the edge sealer 130 in a machine direction 134, a pleat folder 136 forms pleats (step 214 of FIG. 2) in the multi-layer mask web 108 that allow the web 108 to be stretched to increase a covering area for a user's face. An optional patch placement assembly 138 may attach (step 216 of FIG. 2) reinforcement patches adjacently to the longitudinal edges of the multi-layer mask web 108 at the attachment zones to which the elastic straps disclosed herein will be affixed. The optional reinforcement patches may be applied, for example, to the inner layer 114 to reinforce the coupling of the elastic straps to the multi-layer mask web 108. Manufacturing line 100 may also include one or more optional edge wrap units (not shown) configured to wrap material about one or both lateral edges of the multi-layer mask web 108.
An end seal unit 140 receives the multi-layer mask web 108 and seals or joins the outer and inner layers 110, 114 together (step 218 of FIG. 2) in an end seal location extending in a cross-machine direction 142 at locations along the multi-layer mask web 108 corresponding to separation zones from which individual masks may be separated into individual units. The end seal locations overlap and extend away from their corresponding separation zones such that when an individual mask unit is separated from the web 108, the joint of the outer and inner layers 110, 114 created by the separated end seal location forms an end edge seal.
In a different portion of manufacturing line 100, an elasticized strap web 144 is formed to provide elastic straps to be attached to the multi-layer mask web 108 to form straps stretchable around the head of a user to keep the mask unit in place. As shown, the elasticized strap web 144 may be simultaneously created with the creation of the multi-layer mask web 108. Alternatively, the elasticized strap web 144 may be supplied from a spool where the elasticized strap web 144 has been previously created in a prior process. In the embodiment shown, a strap web 146 is provided (step 220 of FIG. 2), and a one or more tensioned elastic strands or structures 148 are joined (step 222 of FIG. 2) to the strap web 146, in one embodiment, by adhesive applied from an adhesive applicator 150 before or after the elastic strands are brought next to the strap web 146. While three elastic strands 148 are illustrated in FIG. 1, embodiments of the invention contemplate that any number of elastic strands may be used including a single strand. In addition or alternatively thereto, elastic film or other stretchable materials such as rubber may be used.
In the case where the elastic straps are formed from a single layer of strap web material 146 as illustrated, a folder 152 may fold (step 224 of FIG. 2) one portion of the strap web 146 over another to create inner and outer layers of strap web material between which the plurality of elastic strands 148 is positioned. In an embodiment not using adhesive, a non-adhesive bonding unit 154 (shown in phantom) may be used in place of the adhesive applicator 150 to create a glue-less elastic strap. The non-adhesive bonding unit 154 may utilize any known welding or bonding techniques that fuse together two or more material layers without the use of adhesive, including sonic, thermal, or pressure bonding techniques and various other forms of welding known in the industry. In other words, the non-adhesive bonding unit 154 may be an ultrasonic bonding unit, a thermal bonding unit, or a pressure bonding unit, according to alternate embodiments. According to one non-limiting embodiment, non-adhesive bonding unit 154 may be configured in a similar manner as any of the bonding units disclosed in U.S. Ser. Nos. 16/260,259, 16/717,186, and 16/721,414 filed by Curt G. Joa, Inc. of Sheboygan Falls, Wis., the disclosures of which are incorporated herein by reference in their entireties.
In the embodiment shown, a single assembly line for forming elasticized strap web 144 is used to form and split (step 226 of FIG. 2) the elasticized strap web 144 into two or more elastic straps by a cutter/slitter 156. However, it is contemplated that multiple assembly lines may be used for creating corresponding multiple lines of elasticized strap webs 144. In this case, the cutter 156 may be eliminated. Furthermore, it is contemplated that the cutter/slitter 156 may be omitted in embodiments where a single, wide elastic strap may be used to secure the individual mask unit to the user wherein the single strap is attached to the mask at the side edges of both the top and bottom portions of the mask.
Manufacturing line 100 may further include an optional friction enhancing unit 153 downstream from the folder 152. In one embodiment, unit 153 may be a cut-and-place unit that cuts and positions patches of material on the elasticized strap web 144 that enhance the friction of the strap web 144 and aid in maintaining the straps in position when the completed mask is in use. These patches of material may be secured to the elasticized strap web 144 via adhesive, sonic, thermal, or pressure bonding, or any other known securement means. In alternative embodiments, unit 153 may be a feed unit that couples a continuous web of friction-enhancing material to the surface of the strap web 144. In yet other embodiments, the frictional properties of the strap web 146 may be enhanced via application of a coating or surface treatment of the material itself.
Application of the elastic strands 148 to the strap web 146 occurs while the elastic strands 148 are in a stretched state. The result is an elasticized strap web 144. The tension in the elasticized strap web 144 is relaxed or partially relaxed prior to its attachment to the multi-layer mask web 108. In one embodiment, the manufacturing speed of the elasticized strap web 144 is faster than the manufacturing speed of the multi-layer mask web 108. For example, the manufacturing speed of the elasticized strap web 144 may be 900-1000 ft./min. while the manufacturing speed of the multi-layer mask web 108 may be 300 ft./min. Thus, when in a relaxed state matching the length of the mask, the elasticized strap web 144 may offer a stretch of up to three times the length of the mask.
Therefore, in order to attach the elasticized strap web 144 in a relaxed or partially-relaxed state to the multi-layer mask web 108, the manufacturing speed of the elasticized strap web 144 must be slowed down to correspond with the manufacturing speed of the multi-layer mask web 108. A retraction assembly 158 retards (step 228 of FIG. 2) the elasticized strap web speed prior to the attachment of the elasticized strap web 144 to the multi-layer mask web 108. In one embodiment illustrated in FIG. 1A, the retraction assembly 158 includes a plurality of rollers 160 arranged in an “s-wrap” configuration configured to allow the speed of the elasticized strap web 144 to decrease between rollers 160. Two or more rollers 160 may be used to retard the elasticized strap web speed. Rollers 160 may be powered or free-rolling. In another embodiment illustrated in FIG. 1B, multiple pairs of nip rollers 162, 164 may be used and actively controlled to slow down the manufacturing speed of the elasticized strap web 144. For example, nip rollers 162 may be controlled to reduce the speed of the elasticized strap web 144 to a speed half of the difference (e.g., 600 ft./min. using the example numbers above) between the elasticized strap web speed and the multi-layer mask web speed. Nip rollers 164 may then be used to reduce the speed of the elasticized strap web 144 to a speed substantially matching the multi-layer mask web speed. It is contemplated that more pairs of nip rollers may be used to create more slowdown stages if desired.
Downstream of the end seal unit 140, the one or more continuous elasticized strap webs 144 are brought together with the multi-layer mask web 108, while the one or more continuous elasticized strap webs 144 and the multi-layer mask web 108 are traveling in the machine direction 134, and provided to a strap bonding module 166 that bonds (step 230 of FIG. 2) the one or more elasticized strap webs 144 in attachment zones or bond sites 805 (FIG. 8) that are spaced apart in the machine direction 134 and correspond with the end seal locations 700 (FIG. 7) sealed by the end seal unit 140. Strap bonding module 166 may be similar to any of the embodiments described above for edge sealer 130 or may include other types of attachment methods including, for example, stapling. In the case where the strap bonding module 166 adhesively joins the one or more elasticized strap webs 144 to the multi-layer mask web 108, an adhesive applicator 168 may apply adhesive for the attachment. The one or more elasticized strap webs 144 are positioned along the multi-layer mask web 108 so that both webs 108, 144 run together in the machine direction 134 for attachment. The straps, when bound in this manner, extend along the length direction 807 (FIG. 10) of the individual mask units 172 (FIG. 10) when separated rather than along the width direction 809 (FIG. 10) as known in the art.
After the one or more elasticized strap webs 144 are bonded with the multi-layer mask web 108, a cutting assembly 170 forms masks (step 232 of FIG. 2) from the resulting continuous face mask composite structure 234 in preparation for packaging. Cutting assembly 170 may have a knife to completely cut through the combined webs 108, 144 to individualize discrete mask units 172 at the separation zones or may have a perforation unit that forms perforations through the combined webs 108, 144 to apply a perforation along the separation zones that allows an end user to tear individual masks from a continuous mask web. Thereafter, the individualized mask units (or the perforated mask web) are provided to a packaging unit 174 for packaging the individual or perforation-formed masks as desired. For example, the masks may be individually packed or bagged or boxed as a group of masks.
Referring to FIG. 3, a schematic diagram illustrating the multi-layer mask web 108 after the step 208 of folding the longitudinal edges 122, 124 of the outer layer 110 over the inner layer 114 is shown. FIG. 4 illustrates a schematic diagram showing the multi-layer mask web 108 after the step 210 of edge sealing the longitudinal edges 122-128 of the outer and inner layers 110, 114. Attachment zones 400 of adhesive or individual ultrasonic bond points, for example, are shown. As illustrated, additional attachment zones 402 may be positioned adjacently to ends of the bendable strips 102 to further secure against movement along the length direction of the individual masks.
Referring to FIG. 5, a schematic diagram illustrates the multi-layer mask web 108 after the step 214 of forming pleats 500 therein. FIG. 6 illustrates a schematic diagram showing the multi-layer mask web 108 after the optional step 216 of placing reinforcement patches 600. While pairs of patches 600 are illustrated on opposite sides of the multi-layer mask web 108, a single patch 600 may be placed across the width of the multi-layer mask web 108 or a subportion of the width, such as in a patch extending through the central section of the mask web 108, in other embodiments.
Referring to FIG. 7, a schematic diagram illustrates the multi-layer mask web 108 after the step 218 of joining the outer and inner layers 110, 114 together at end seal locations 700. FIG. 8 illustrates a schematic diagram showing the resulting continuous face mask composite structure 234 after the step 230 of bonding separated elasticized straps 800, 802 to the multi-layer mask web 108. As shown in FIG. 8, the separated straps 800, 802 are bonded to the multi-layer mask web 108 at locations adjacent the respective top longitudinal edge 801 and the bottom longitudinal edge 803 of the multi-layer mask web 108. FIG. 9 illustrates a schematic diagram showing the separation zones 900 in the continuous face mask composite structure 234 along which the continuous face mask composite structure 234 is to be cut to individualize discrete mask units 172 (FIG. 10) or along which the continuous face mask composite structure 234 is to be perforated as described above.
FIG. 10 provides a top plan view of an individual mask unit 172 with elasticized straps 1000, 1002 corresponding respectively to separated elasticized straps 800, 802 of FIG. 8. Referring to FIG. 11, a side plan view of the individual mask unit 172 is illustrated showing elasticized strap 1000 in a relaxed state. As shown in FIG. 11, the elasticized strap 1000 has a ruffled appearance in the relaxed state due to the gathering of strap web 146. FIG. 12 illustrates the elasticized strap 1000 in a stretched state to allow the elasticized strap 1000 to be positioned around the head of a user. As previously discussed, the length of the elasticized strap 1000 in the stretched state as illustrated in FIG. 12 may be, for example, three times the length of the elasticized strap 1000 in the un-stretched or relaxed state as illustrated in FIG. 11. Other ratios of the length of the elasticized strap 1000 in its stretched state to its relaxed state are available, however, and contemplated herein. For example, an elasticized strap 1000 formed from the elasticized strap 800 may have a different stretch ratio than elasticized strap 1002 formed from the elasticized strap 802 on the same discrete mask 172. One may have a 3:1 ratio while the other may be different such as a 2:1 ratio. In addition, an elasticized strap 1000 formed from the elasticized strap 800 may have a different attachment tension to the mask 172 than elasticized strap 1002 formed from the elasticized strap 802 on the same discrete mask 172.
In an alternative embodiment, FIG. 13 illustrates a side plan view of the individual mask unit 172 where the length of the mask is longer than the length of the elasticized strap 1000 in its relaxed state. As shown, the multi-layer mask web portion of the mask unit 172 may be folded in preparation for packaging to account for its longer length compared with the length of the elasticized strap 1000. In another embodiment shown in FIG. 14, the length of the elasticized strap 1000 in its relaxed state is longer than the length of the mask unit 172. Accordingly, the elasticized strap 1000 may be folded if desired to account for its longer length for packaging.
FIG. 15 illustrates a schematic diagram of an embodiment of the elasticized strap web 144 in either an adhesive-based construction or an adhesive-less elastic entrapment construction. As shown, deactivation zones 1400 may be formed by not applying adhesive or not forming entrapment bonds in areas 1400 to have elastic deactivation and breaking the elastic threads 148 that span the areas 1400, causing the elastic threads 148 to retract toward opposite sides of the deactivation zone 1400 to the point where the elastic threads 148 are trapped by either adhesive or entrapment bonds. The elastic threads 148 may be broken by being cut with a cutting unit (not shown) configured to cut the elastic threads 148 using a knife or by being pinched to a breaking point with a crushing apparatus. Adhesive-less elastic entrapment construction involving entrapment bonds and deactivation zones is described in U.S. Publication No. 2019/0234606 and assigned to Curt G. Joa, Inc. of Sheboygan Falls, Wis., which is incorporated herein by reference in its entirety.
Embodiments of the invention described herein provide a number of improvements over prior art face masks. The resulting mask structure includes a ruffled elastic strap that is more comfortable to wear and more breathable. The disclosed methods of manufacturing the elastic straps facilitates forming straps with adjustable tension to create an improved fit. The mask is held in place while in use due to the ruffled profile of the strap alone or in combination with other friction-enhancing materials or surface textures. The disclosed method of manufacture also permits masks to be formed at a higher speed that prior art methods, as the masks do not need to be turned 90 degrees prior to attaching the straps.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description but is only limited by the scope of the appended claims.
Patent Application
20230136249
