Improvements to face masks

Abstract

The present invention provides a face mask for filtering air and a method for manufacturing the same. [Solution] The method includes using an overmolding step for both forming the sealing member and fixing the sealing member to the support frame and the sheet of filter material.

Description

Technical Field

[0001] The present invention relates to a face mask, particularly a face mask for filtering air, i.e., a filter mask, a method for manufacturing the same, and a face mask manufactured by the disclosed method.

Background Art

[0002] Face masks for filtering and removing particulate matter from air, i.e., filter masks, are typically one of two types. In particular, a face mask can have a mask body that functions to filter and remove particulate matter from air itself, and this type of filter mask is typically lightweight and relatively inexpensive to be single-use and disposable. Alternatively, the face mask may have a mask body adapted to receive a replaceable filter cartridge so as to be reusable.

[0003] Filter masks can be worn in work or public environments to protect against dust, smoke, and other harmful substances, as well as to protect against pathogens such as viruses or bacteria. For example, in a medical environment, filter masks are used to prevent inhalation of pathogens from the environment by preventing fine particles, such as droplets and aerosols, from passing through the mask. Filter masks can also protect others from the exhaled breath of the wearer carrying pathogens.

[0004] Filter masks typically comprise a filter, such as a sheet of woven or non-woven filter material, and means for holding the mask on the wearer's head, such as elastic loops disposed around the ears. In use, the filter covers the user's mouth and nose or is otherwise oriented so that air passes through the filter, such that all air inhaled by the wearer passes through the filter. To protect others from the exhaled breath of the wearer carrying pathogens, the filter can be arranged so that all air exhaled by the wearer passes through the filter.

[0005] Filter masks worn by medical professionals and others in the workplace must fit snugly to the face and be comfortable to wear for extended periods in environments where the risk of contamination may be high. Such masks must fit snugly to the wearer's face, preferably forming a seal to the face to prevent inhaled and exhaled air from passing around the edges of the mask.

[0006] Filter masks are generally single-use products that are manufactured and sold in large quantities. To make this type of product commercially viable, manufacturing costs and complexity must be kept to a minimum. [Overview of the project] [Problems that the invention aims to solve]

[0007] Herein, a face mask for filtering air and a method for manufacturing the same have been developed that overcome or substantially mitigate the aforementioned problems and / or other problems related to the prior art. [Means for solving the problem]

[0008] According to a first aspect of the present invention, a method for manufacturing a filter mask is provided, the filter mask comprising a support frame, a filter, and a sealing member, and the method is a) Placing the filter and support frame inside the mold, b) injecting polymer material into a mold to form a sealing member, The sealing member is engaged with the filter and support frame so as to fix the sealing member to the support frame and the sheet of filter material during the injection molding of the sealing member.

[0009] The injection molding of the sealing member in the method according to the present invention may be an overmolding process. In the context of the present invention, "overmolding" means an injection molding process in which a first material is molded on a second material to form a single article, and the first material partially or completely covers the second material.

[0010] A method for manufacturing a filter mask according to a first aspect of the present invention is advantageous because the step of injection molding a sealing member fixes the sealing member to the support frame and the sheet of filter material, and thus the relative positions of these components can be fixed without requiring any further assembly or molding steps. Face masks, especially filter masks, are mass-produced and sold at low cost. Since the profit margin on each individual item is low, reducing the cost and complexity of the manufacturing method is key to producing a viable product.

[0011] A further aspect of the present invention provides a filter mask manufactured according to the method described above. A further aspect of the present invention provides a filter mask comprising a support frame, a filter, and a sealing member, wherein the sealing member is fixed to the support frame and the filter.

[0012] The support frame and filter together can define a mask body that forms a cavity for accommodating the wearer's mouth and nose. The mask body may be curved, at least in cross-section.

[0013] The support frame may be manufactured in a prior step of the method of the present invention. The support frame may be manufactured by injection molding in a prior step. Therefore, the method may further include a prior step in which the support frame is formed by injection molding. The method may further include a step of transferring the support frame from a first mold in which the support frame is injection molded to a second mold in which the sealing member is injection molded.

[0014] The support frame may be made from plastic materials such as polypropylene, poly(styrene-butadiene-styrene) (SBS), polycarbonate, plastomer, thermoplastic, thermoplastic elastomer, thermosetting material, or blends or combinations thereof.

[0015] The support frame may have an outer surface and an inner surface, the inner surface facing the wearer during use, and the outer surface facing away from the wearer during use.

[0016] The support frame can support at least a portion of the filter, for example, by preventing distortion of the filter material sheet. The support frame can provide rigidity to the mask.

[0017] The support frame may take the form of a rim, for example, that matches the shape of the filter material. The rim may have a closed-loop shape. The rim can define an opening through which inhaled and / or exhaled air flows during use. When the filter is placed on the support frame, the support frame may extend around the periphery of the filter. The support frame may have shoulders extending from the inner edge of the rim, which provide a surface on which the filter can be placed and facilitate the retention of the filter in the mold before injection molding of the sealing member. The filter may be placed on the inner surface of the support frame.

[0018] In place of or in addition to the rim, the support frame may include one or more ribs, for example, multiple ribs, extending across the surface of the filter to provide support to the filter and rigidity to the mask.

[0019] The outer surface of the support frame may further comprise a shield extending over at least a portion of the filter surface in the filter mask according to the present invention. The shield may be separate from the filter, and air may flow between the shield and the filter, for example, before air is drawn through the filter by the wearer during inhalation. Therefore, a space or gap may exist between the shield and the filter. An inlet opening into which air can be drawn in by the wearer's inhalation may be defined between the edge of the shield and the surface of the filter.

[0020] The shield can provide a barrier to which particles in the environment collide. Therefore, the shield can reduce the amount of particles that hit the filter during use, and thus can extend the effective life of the filter, and therefore the filter mask. The separation between the shield and the filter allows incoming air to flow through the filter across its entire surface, even if the shield is impermeable or substantially impermeable. The shield further provides reinforcement to the mask, preventing it from collapsing in the longitudinal direction and keeping the mask in the correct position relative to the wearer's nose and chin.

[0021] The shield may be formed from a plastic material. This allows for the formation of a solid barrier to deflect particles, thereby reducing the risk of physical damage to the filter by providing a protective barrier. The shield may also form a rigid barrier.

[0022] Alternatively, the shield may be a composite shield formed from two or more components. The composite shield may comprise a sheet of filter material (shield filter) and a shield frame, the shield filter being superimposed on and attached to the shield frame. The shield frame may be a plastic frame and may form part of a support frame. The shield frame may comprise a shield rim substantially the same shape as the intended shield and / or shield filter, the shield rim being attached to the periphery of the shield filter. Such a composite shield can actively absorb and block contaminants and reduce moisture buildup inside the mask, thereby enhancing wearer comfort. The composite shield may be detachably attached to the mask so that it can be replaced when saturated, and either the entire composite shield is detachable and replaceable, or only the sheet of filter material is replaceable.

[0023] According to a further aspect of the present invention, there is provided a filter mask comprising a support frame, a filter, and a sealing member, wherein the support frame holds the filter such that ambient air is drawn through the filter upon inhalation by the wearer, and the support frame includes a shield extending over at least a portion of the outer-facing surface of the filter, the shield being separated from the filter, and during use, air flows between the shield and the filter before the air is drawn through the filter by the wearer during inhalation.

[0024] According to a further aspect of the present invention, there is provided a filter mask comprising a support frame, a main filter, and a sealing member, wherein the support frame holds the main filter such that ambient air is drawn through the main filter upon inhalation by the wearer, and the support frame includes a shield frame carrying a shield filter extending over at least a portion of the outer-facing surface of the main filter, the shield frame being separated from the main filter such that during use, air flows between the peripheral edge of the shield frame and the main filter.

[0025] In the following paragraphs, unless otherwise indicated, references to "shield" refer to both shields formed from plastic materials and composite shields formed from shield frames and shield filters. Additionally, unless otherwise indicated, references to "filter" refer to the main filter, i.e., the filter held by the support frame, and references to "shield filter" refer to the filter forming part of the composite shield.

[0026] The support frame may comprise a rim and a shield, or a rim and a shield frame, and the shield or the shield frame may be offset from the rim, for example, in a cross-section. The rim may extend around and / or over the peripheral portion of the filter, and the shield or the shield frame may be offset from both the rim and the filter. The rim and the shield or the shield frame may be connected together by one or more connecting members that extend between the shield and the rim and can fix their relative positions. For example, the connecting member may extend between the rim and the shield or the shield frame at three, or four, or five points, and these points may be regularly spaced around the rim.

[0027] The shield may be offset from the filter, for example, in a cross-section, may have a shape corresponding to the shape of the filter, and the surfaces of the filter and the shield are parallel.

[0028] When measured along a line perpendicular to the surface of the shield, there may be an interval having an average size of 0.1 - 5 cm, or 0.2 - 2.5 cm, or 0.2 - 1.5 cm, or 0.3 - 1 cm between the shield and the filter. This interval between the shield and the filter may be maintained by one or more ribs that extend over at least a part of the surface of the shield facing the filter. The ribs may be linear or arcuate. The ribs may contact the filter, prevent the shield from contacting the filter material, and thus maintain the air flow between the shield and the filter material even while the wearer is moving.

[0029] The surface area of ​​the shield may be at least 50%, at least 60%, at least 70%, or at least 80%, at least 90%, or at least 95% of the surface area of ​​the filter. The surface area of ​​the shield may be up to 110%, or up to 105%, up to 100%, or up to 95% of the surface area of ​​the filter. The shield may extend over at least 50%, at least 60%, at least 70%, or at least 80%, at least 90%, at least 95%, or up to 100% of the surface area of ​​the filter.

[0030] The shield may extend across the entire surface area of ​​the filter, or it may extend beyond the periphery of the filter so that the shield overhangs the edges of the filter. Alternatively, the shield may extend over less than 100% of the surface area of ​​the filter so that a portion of the filter is exposed at the periphery of the shield. Alternatively or additionally, the shield may have openings that expose sheets of filter material, which can assist airflow to help uniformly distribute the particle load on the filter. Alternatively, the shield may have no openings and form a continuous barrier. Thus, the shield may have a continuous surface that extends over most of the surface of the filter material.

[0031] A space may exist between the edge of the shield and the rim of the support frame, through which the filter is exposed to the environment, and this exposure is caused by the horizontal offset of the shield from the filter and / or the shield extending over less than 100% of the filter's surface area. The offset of the shield from the filter and / or partial covering of the filter by the shield allows airflow around the shield and through the filter, ensuring that the entire surface area of ​​the filter material is used while the wearer breathes.

[0032] At the same time, the shield itself protects part or most of the filter. The shield can, for example, capture some of the airborne particles, such as aerosol particles and / or other contaminants, that come into contact with the mask, preventing them from coming into contact with the filter. This extends the life of the mask by increasing the time it takes for the filter to become saturated. The shield also reduces the risk of damage to more delicate filters and prevents or prevents the wearer from touching potentially contaminated filters while handling the mask.

[0033] At least a portion of the periphery of the shield may be separated from the rim of the support frame, thereby defining one or more inlet openings through which air is drawn when the wearer inhales. The one or more inlet openings may be arranged in loops or partial loops to allow closure by the wearer's fingers in order to perform a fit test. In particular, prior art tests for the fit of a face mask on a wearer typically involve expensive testing equipment or are not easily performed by the wearer themselves. The arrangement of one or more inlet openings in loops or partial loops to allow closure by the wearer's fingers allows the wearer to then test whether air leaks into the mask when one or more inlet openings are closed, thereby testing the fit of the mask. In particular, if the face mask fits effectively, the wearer should not be able to inhale when one or more openings are closed.

[0034] A further aspect of the present invention provides a filter mask comprising a support frame, a filter, and a sealing member, wherein the support frame holds the filter so that ambient air is drawn through the filter when the wearer inhales, and the filter mask includes a shield extending over at least a portion of the outward-facing surface of the filter, with at least a portion of the periphery of the shield separated from the support frame, and one or more inlet openings defined between the shield and the support frame through which air is drawn when the wearer inhales.

[0035] The separation between the periphery of the shield and the support frame is preferably less than the width of an average person's finger, such as an index finger, for an adult mask or a child's mask. For example, the separation between the periphery of the shield and the support frame may be less than 2 cm, less than 1.5 cm, or less than 1 cm.

[0036] One or more entry openings may be positioned along the entire periphery of the shield, or they may be separated by members connecting the support frame and the shield. One or more entry openings in the nose and / or chin regions may extend outward along a curved path from an angled apex in the central region of the mask toward the side of the mask to receive the wearer's fingers during fit testing, with the fingers meeting at the angled apex. Alternatively, or in combination, one or more entry openings in the nose and / or chin regions may extend in a regular curved path from one side of the mask toward the other to receive the wearer's fingers during fit testing, with the fingers meeting at the midpoint of the curved path. One or more entry openings in the side regions of the mask may be aligned with the longitudinal axis of the mask and the wearer, i.e., the axis from the nose region to the chin region, and may be in a substantially linear form to receive, for example, a portion of the wearer's hand between the index finger and thumb during fit testing.

[0037] Alternatively, one or more inlet openings may be positioned around a portion of the periphery of the shield. In particular, the inlet openings may be positioned around the cheek and / or chin area, with no inlet openings in the nose area. This arrangement can direct the exhaled airflow away from the wearer's eyes, enhancing wearer comfort and reducing or preventing fogging of the wearer's glasses. The fit tests described in the preceding paragraphs can still be performed on the openings in this arrangement.

[0038] Alternatively, the mask may be provided with one or more covers for the entrance openings, thereby allowing the openings to be closed without the wearer using their fingers to close them. Accordingly, a kit of components is also provided, comprising a filter mask according to the above-described aspect of the present invention and one or more covers for the entrance openings, the covers allowing the openings to be closed for fitting testing.

[0039] Further arrangements to facilitate fit testing include means of generating an odor on the mask, which would then be filtered out. For example, the mask could include an element for releasing an odor onto the outside of the filter and a cover for suppressing the odor before use, the cover being at least partially removed, for example, by being peeled or scratched, to at least partially expose the element for releasing the odor. The wearer should not be able to detect an odor if the face mask fits effectively.

[0040] A further aspect of the present invention provides a filter mask comprising a support frame, a filter, and a sealing member, wherein the support frame holds the filter so that ambient air is drawn through the filter from the outside to the inside of the filter when inhaled by the wearer, and the filter mask includes an element for releasing odor onto the outside of the filter.

[0041] The filter mask may be equipped with a cover to suppress odor before use, and the cover may be at least partially removable to at least partially expose the elements that emit the odor. The cover can reduce the risk of the odor being transferred to other parts of the filter mask, such as the inside of the filter. Furthermore, the cover may be removed once the mask is fitted to ensure that the fit test is not affected by the wearer detecting the odor before the test.

[0042] The filter may be sufficiently impermeable to odors so that the wearer does not detect odors in the air drawn through the filter. The elements may be exposed to release odors only on the outside of the filter, and as a result, the wearer should not be able to detect odors if the face mask fits effectively.

[0043] The odor-releasing elements may include or be placed on a part of the support frame, such as a shield or part of a shield, or the odor-releasing elements may be applied to the entire support frame. If the elements are applied to the entire support frame, any part of the support frame on the inside of the filter may need to be covered in a way that suppresses odor, for example by overmolding a thermoplastic elastomer cover.

[0044] The support frame may include a shield extending over at least a portion of the outward-facing surface of the filter, with at least a portion of the periphery of the shield separated from the support frame. One or more inlet openings may be defined between the shield and the support frame, through which air is drawn in when the wearer inhales.

[0045] The support frame is typically formed from a plastic material that maintains its shape during use. The support frame may comprise a rim and / or a shield and / or one or more connecting members. If multiple components exist, the entire support frame may be formed integrally, for example by injection molding, or the support frame may be formed from two or more parts that are joined together, for example by bonding, welding, or mechanical fastening. Therefore, if the support frame comprises a rim and a shield, the rim and shield may be formed integrally in a single injection molding step, or the rim and shield may be formed separately and then joined together either chemically or mechanically.

[0046] The filter may be formed from a filter substrate that is sufficiently dense to prevent the passage of most suspended particles, such as dust particles, droplets, and aerosols. The mask of the present invention can filter out at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 99% of suspended particles.

[0047] In countries including the United Kingdom and the European Union, FFP standards specify the requirements for filter masks as respiratory protective devices. The EN149 standard defines three classes of filter efficiency: FFP1, FFP2, and FFP3. The mask of the present invention may be, for example, an FFP3 mask, which, under the EN149 standard, filters out at least 99% of airborne particles at an airflow of 95 L / min with total internal leakage of less than 2%. The mask of the present invention may be an FFP2 mask, which filters out at least 94% of airborne particles at 95 L / min with total internal leakage of less than 8%. In the United States, the National Institute for Occupational Safety and Health (NIOSH) provides the N95 classification for air filtering, and the mask of the present invention may be an N95 mask, which means filtering out at least 95% of airborne particles.

[0048] Suitable materials for use as filter substrates are known in the art, and any suitable material can be used for the filter material sheet in the present invention. For example, the filter may be a nonwoven material, an electrostatic material, a meltblown material, a spunbond material, a woven material, a nanofiber material, or a nanoweb material, or it may be formed from a glass fiber medium. The filter may include multiple layers to enhance its performance and improve wearer comfort. Therefore, the filter may include one or more layers selected from nonwoven materials, electrostatic materials, meltblown materials, spunbond materials, woven materials, nanoweb materials, and / or nanofiber materials. For example, the filter may include layers of nonwoven material, an electrostatic material, and a meltblown material together with a fiber layer to improve wearer comfort and provide structure to the filter. The filter may have any suitable configuration; for example, the surface of the filter may be smooth, for example, flat or planar, or the filter may be pleated. The filter (with or without pleats) may have a flat or planar area around its periphery to facilitate the overmolding process. The filter may further contain one or more additives to enhance its effect in reducing or preventing the transmission of pathogens, such as antimicrobial agents.

[0049] The use of pleated filters improves their effectiveness by increasing their surface area. Pleating a filter can increase its surface area by 5-50%, 5-30%, or 10-20% compared to an unpleated filter. To accommodate a pleated filter, the shape of the support frame may correspond to the shape of the pleated filter, ensuring a tight fit between the two components and preventing leakage. For example, if the filter contacts a shoulder or rim on the support frame, the shoulder or rim may have a series of corrugations corresponding to the filter's pleats, so that when the filter contacts the shoulder or rim, the corrugations nest with the filter's pleats, ensuring a tight fit. The filter may be pleated before being placed in the mold together with the support frame, and the sealing member may be overmolded to secure the sealing member, support frame, and filter together. Alternatively, pleats may be formed within the filter by compressing a non-pleated (i.e., flat or planar) filter between the corrugated rim or shoulder of the support frame and a mold of a corresponding shape before overmolding the seal member to secure the seal member, support frame, and filter together.

[0050] In the method of the present invention, the filter placed in the mold may consist only of a filter substrate and may have a flexible shape. The filter may not include a support for the filter substrate until it is fixed to the support frame and sealing member.

[0051] The filter may be cut to the correct shape from a larger sheet of filter substrate, for example, using a die. If the filter is formed from multiple layers, the filter may be cut to size, and the edges may be sealed in a single hot stamping process, where heat is used to seal the peripheral edges of the seal during the cutting process. The sealed edges prevent moisture or contaminants from entering the interior of the filter material between layers during use. The size and shape of the filter may correspond to the size and shape of at least a portion of the support frame. For example, the size and shape of the filter may correspond to the size and shape of the rim of the support frame, thereby allowing the filter to be positioned on the rim, for example, on a shoulder extending inward from the rim, such that the support frame extends around the periphery of the filter.

[0052] In some embodiments, the filter can be brought into contact with the support frame before the support frame and filter are both placed in the mold. For example, the filter may be placed on the rim of the support frame before the support frame and filter are both placed in the mold. Alternatively, the support frame may be placed in the mold before the filter is positioned on the support frame. In either case, both the support frame and the filter are placed in the mold before injection molding of the sealing member. Preferably, the support frame and the filter material sheets are neither fixed nor bonded together before being placed in the mold.

[0053] The sealing member is fitted to the wearer's face and overmolded around both the filter and the support frame. Thus, the filter and support frame are positioned within the mold, and their relative positions are fixed by the injection molding of the sealing member. This allows the support frame, filter, and sealing member to be fixed together in a single step without the need for additional adhesive or overmolding steps, thereby reducing time and cost.

[0054] To secure the filter and support frame together in a single overmolding step, the filter may be positioned on the outer or inner surface of the support frame, for example, on the rim, such that the edges of the filter material sheet and the support structure are substantially aligned. During the injection of the polymer material forming the sealing member, a portion of the polymer material can enclose the aligned edges of the filter material sheet and the support structure. Thus, the peripheral edges of both the filter and the support frame, or the rim of the support frame, can be enclosed within a portion of the polymer material forming the sealing member.

[0055] Alternatively, during the overmolding of the seal, the injected material may be directed between the filter and the support frame so that the injected material forms an adhesive layer between the filter and the support frame around the periphery of the filter. The periphery of the filter may be wrapped by the injected material, which then bonds to the support frame (e.g., to the rim of the support frame). The injected material may be absorbed into the filter around the periphery of the filter, enhancing the bond between the seal and the filter and providing additional protection against moisture intrusion between the layers of the filter material.

[0056] "Substantially aligned" means that the edges of the filter material and the support structure are positioned close together so that they can be wrapped by a portion of the sealing member or otherwise bonded together.

[0057] The sealing member may be formed from an elastomer material, and suitable materials for use in manufacturing sealing members for face masks are known in the art. For example, the sealing member may be formed from a thermoplastic elastomer (TPE) or thermosetting elastomer, such as liquid silicone rubber.

[0058] The sealing member may be molded to fit snugly against the wearer's face and seal it so that all the air inhaled by the wearer passes through the filter material. To enhance comfort and sealing effect, the sealing member may be in the form of a cushion. That is, the sealing member can create an elastically compressible area between the support frame and the wearer's face to enhance comfort and improve the seal.

[0059] The effectiveness of masks improves with improved fit (and reduced leakage), so it is useful that there are masks that can adapt to different face sizes and remain effective even when the wearer moves and takes on an active role, such as filter masks used by medical professionals.

[0060] Any embodiment of the support frame and / or seal may contain one or more additives to help enhance the effectiveness of the mask in reducing or preventing the spread of bacteria or other pathogens. In particular, additives containing silver ions (e.g., in the form of Silver Knight®) may be incorporated into the plastic of the support frame and / or seal. Silver ions have been found to catalyze the inactivation of pathogenic bacteria and prevent their growth, thereby reducing microbial growth inside and on the surface of the mask.

[0061] A further aspect of the present invention provides a filter mask comprising a support frame and a sheet of filter material, wherein the support frame and the sheet of filter material define a mask body adapted to provide a cavity around the wearer's mouth and nose when in use, and the filter mask includes a sealing member hanging down from at least a portion of the peripheral edge of the mask body, the sealing member comprising a lip portion hanging down both inward and outward relative to the peripheral edge of the mask body.

[0062] The sealing member may extend around the entire peripheral edge of the mask body. A portion of the peripheral edge of the support frame, around which the inwardly and outwardly hanging lip portions extend, may constitute the chin portion. The inwardly hanging lip portions may extend around most of the peripheral edge of the support frame. The outwardly hanging lip portions may extend around only a portion of the peripheral edge of the support frame, for example, within the chin region.

[0063] The inwardly hanging lip portion may be substantially flat. The inwardly hanging lip portion may take the form of an upright wall that follows the contour of the peripheral edge of the main body. The inwardly hanging lip portion may include discontinuities that facilitate deformation of the inwardly hanging lip portion.

[0064] The outward-hanging lip portion may have a concave contact surface. The outward-hanging lip portion may be molded to provide a base or shelf-forming portion under the wearer's lower jaw. The proximal portion of the outward-hanging lip portion may engage with the wearer's jaw, while the distal portion may curve and extend under the wearer's jaw. The outward-hanging lip forming portion may be molded in the form of a chin cup. The chin cup may accommodate at least a portion of the wearer's jaw when in use. The outward-hanging lip portion may be molded to provide both an anterior lip portion and an posterior lip portion.

[0065] The inwardly hanging lip portion may contact the lower part of the wearer's face, for example, the wearer's chin, to form a seal. If the user has a greater face height, the outwardly hanging lip portion may pass just below the wearer's lower jaw to provide an additional seal. For all wearers, the outwardly hanging lip portion can provide an alignment guide for positioning the mask on the face and help keep the mask in the correct position on the face even if the chin moves during use.

[0066] The peripheral portion of the support frame near the inner and outer lip portions may be formed by a first radius from the center point or region of the mask. The inwardly hanging lip portion typically has an inner edge with a radius smaller than the first radius. The outwardly hanging lip portion typically has an outer edge with a radius larger than the first radius.

[0067] The nose portion of the sealing member may include an inwardly hanging lip portion and may have a convex surface for contact with the wearer's face. The nose portion of the sealing member may include reinforcing portions on each side of the nose, for example, portions with increased thickness, or, for example, portions with reduced thickness in the nasal bridge region.

[0068] The sealing member, and therefore the filter mask, may also extend laterally across the wearer's cheek so that a seal is formed between the mask sealing portion and the cheek tissue, and the internal cavity of the mask extends across the cheek.

[0069] During conversation, the majority of facial movement occurs within the jaw, including the vertical separation of the nose and chin, while relatively little movement occurs in the cheeks. In addition, the cheek tissue is softer and more compliant than the tissue of either the nose or the chin. This means that a lower degree of flexibility is required in the sealing material than in other parts of the face to achieve an effective seal with the cheek tissue.

[0070] A further aspect of the present invention provides a face mask comprising a mask body that defines a cavity for accommodating the wearer's nose and mouth, from which the wearer inhales respiratory gases during use, and a sealing member that hangs down from the mask body to engage with the wearer's face, the mask body comprising a nose portion for accommodating the wearer's nose, a mouth portion for accommodating the wearer's mouth, and a cheek portion that extends laterally across the wearer's cheek.

[0071] The cheek portion may extend laterally across the wearer's cheek between the upper edge of the wearer's cheekbone and the lower edge of the lower jaw.

[0072] Each cheek portion may have a first edge extending from the left or right edge of the nose portion, thereby allowing the first edge of the cheek portion to rest on the wearer's cheekbone. The first edge may extend along an arched path. The first edge may also be a concave outer edge. The transition between the first edge of the cheek portion and the left or right edge of the nose portion may be arc-shaped.

[0073] Each cheek portion may have a second edge extending from the left or right edge of the mouth portion, the second edge of the cheek portion being accommodated above the lower edge of the wearer's jaw. The second edge may extend along an arched path. The second edge may be a concave outer edge. The transition between the second edge of the cheek portion and the left or right edge of the mouth portion may be arc-shaped.

[0074] The angle between the first and second edges of each cheek portion may increase as the lateral position improves, and the first and second edges may be substantially parallel at the distal end of the cheek portion, for example, near the wearer's ears. Each edge of the cheek portion may be substantially straight. The distal region of each cheek portion may be substantially rectangular in shape. This can increase the surface area of ​​the mask body covering the wearer's cheeks.

[0075] The mask body may extend a greater distance across the wearer's face transversely than the distance the mask body extends longitudinally across the wearer's face. The greater distance may be relative to the surface of the wearer's face; that is, the distance may be a dimension along the surface of the face, as opposed to a linear dimension.

[0076] The mask body may extend over a distance greater in the transverse direction than over the distance it extends in the longitudinal direction. The greater distance may be relative to the surface of the mask; that is, the distance may be a dimension along or parallel to the surface of the mask, as opposed to a linear dimension.

[0077] The portion of the mask body that accommodates the wearer's nose and mouth may have an outer surface that is, for example, substantially curved in cross-section, while the portion that accommodates the wearer's cheeks may have an outer surface that is, for example, substantially flatter in cross-section. The filter mask and the internal cavity of the filter mask may extend laterally across the wearer's cheeks so that the edges of the mask are positioned within 5 cm, 4 cm, 3 cm, or 2 cm of the wearer's ears when in use. Thus, the mask can substantially cover the wearer's cheeks.

[0078] If the face mask is a filter mask, the mask body may be defined by a support frame and a filter. The sealing member may extend around the periphery of the support frame, for example, around the rim. The shape of at least a portion of the support frame and filter may correspond to the shape of the proximal edge of the sealing member. The support frame and filter may extend laterally across the wearer's cheeks.

[0079] The mask body of the face mask may extend laterally across the wearer's cheeks. The sealing member of the face mask may extend laterally across the wearer's cheeks. The portion of the mask body that extends across the wearer's cheeks can form a shallower cavity between the mask and the wearer's face than the portion of the mask that extends over the wearer's nose and mouth.

[0080] The extension of the mask across the cheeks increases the surface area of ​​the filter material sheet, and therefore increases the volume of air that can pass through the filter. At the same time, the shallower cavities in this region of the mask reduce dead space within the mask.

[0081] The filter mask according to the present invention may include means for securing the mask to the wearer when in use. Such means may include one or more cords or straps, such as elastic cords or straps, that are fitted around the wearer's head to press the filter mask against the wearer's face.

[0082] The cords or straps may be formed as separate single or multiple components and then attached to the filter mask by being inserted through holes or slots and knotted or sealed, or by joining the cords or straps to the mask. The cords or straps may be joined to the mask by adhesive or chemical bonding, or by overmolding. The cords(s) or straps(s) may be worn over the wearer's ears or around the back of the wearer's head. This may help prevent the mask from slipping and / or riding up from the wearer's face during use.

[0083] Two cords or straps may be provided, passing around each of the wearer's ears, or one cord passing over the wearer's ears and the other passing below the ears and extending around the back of the head.

[0084] Alternatively, a single cord may pass twice across the back of the wearer's head. The first side of the support structure may be positioned adjacent to one of the wearer's ears when in use, and the second side of the support structure may be positioned adjacent to the other of the wearer's ears when in use. The first and second sides of the support structure may be positioned in the area of ​​the support structure closest to the wearer's ears when in use.

[0085] The two ends of a single elastic cord or strap may be held by a pair of first mounting parts located on a first side of a support frame, for example, on the side adjacent to one of the wearer's ears. The first mounting parts may be formed integrally with the support frame or formed separately and then attached, for example, by adhesive, welding, or mechanical fastening (e.g., snap-fit ​​fastening). Each of the pair of first mounting parts may hold one end of the cord or strap, and may be a clip or clamp, or an opening or slot through which the cord or strap can pass, with a knot tied to the cord or strap to prevent the cord or strap from slipping back through the slot or opening.

[0086] At least one, for example, one or two attachment forming parts may be positioned on a second side of the support frame, for example, on the side adjacent to the other ear of the wearer, and the attachment forming part(s) may hold the central portion of the cord or strap. Thus, the cord or strap may extend from one of the first attachment forming parts through the second attachment forming part(s), forming a loop of cord and returning to the other of the first attachment forming parts.

[0087] This configuration allows the user to tighten the cord or strap by pulling the loop formed on the second attachment forming section(s), thereby providing an improved tightening configuration that may be beneficial for other types of face masks.

[0088] A further aspect of the present invention provides a face mask comprising a pair of first attachment forming parts and a pair of second attachment forming parts, the pair of first attachment forming parts positioned on first sides of the face mask located near the wearer's first ears when in use, the pair of second attachment forming parts positioned on second sides of the face mask located near the wearer's second ears when in use, each of the pair of first attachment forming parts provides means for securing the end of a strap, and the pair of second attachment forming parts provides means for releasably securing the middle portion of a strap.

[0089] A pair of second attachment forming parts may be positioned on the second side of the support frame, and a cord or strap may pass sequentially through the pair of second attachment forming parts to form a loop of cord between the pair of second attachment forming parts. The second attachment forming parts may allow the cord to pass easily in one direction when tension is applied, but may also present significant resistance to the movement of the cord in the opposite direction without requiring additional action by the user (e.g., pressing a button or applying a significantly greater force). Thus, while wearing the mask, the wearer can easily adjust the length of the strap to fit their head size with one hand by pulling the loop of cord formed between the pair of second attachment forming parts. When tension is applied, the cord slides through the pair of second attachment forming parts, thus shortening the length of the cord around the back of the wearer's head and pressing the face mask against the wearer's face. Once the fit is correct, the user releases the cord, and the mask is held in place by the cord or strap.

[0090] Each of the pair of second mounting forming parts may have a slot or opening substantially covered by a tab. The edges of the tab and / or the corresponding edges of the slot or opening may have means for gripping the cord, such as a rough surface or a series of teeth. In use, the cord or strap is inserted through the slot or opening between the edge of the tab and the edge of the slot or opening. A gripping forming part, such as a series of teeth or rough surfaces along at least one edge of the tab, or along the slot / opening and the corresponding edge of the tab, can prevent the cord or elastic body from slipping back through the slot or opening. The series of teeth may be angled or curved outward, i.e., in the direction in which easy movement of the cord through the slot or opening is desired. Thus, the teeth may be angled or curved away from the slot or opening so that when the cord or strap moves in the reverse direction, the teeth will embed into the cord or strap and facilitate gripping it.

[0091] Alternatively, each of the pair of second mounting forms may comprise a slot or opening and an elastic member, the elastic member substantially covering the slot and elastically biasing it relative to the slot. During use, the cord or strap is inserted through the slot against the bias of the elastic member, and as a result, the tension applied to the strap pulls the elastic member sufficiently away from the slot or opening, allowing the cord to pass through the slot or opening. When the tension on the cord is released, the bias of the elastic member pushes the elastic member back against the slot or opening, closing it and trapping the cord between the elastic member and the edge of the slot or opening. Thus, the cord can be easily pulled through the slot by the application of tension against the bias of the elastic member, but the elastic member can prevent the cord from unintentionally moving in the opposite direction through the slot, even if tension is applied to the cord (for example, when the cord is stretched around the wearer's head). Means for releasing the biased member may be provided to allow the cord to slide in the reverse direction through the slot when the wearer desires, for example, a release catch, or the reverse movement may be activated when a significant force is applied by the wearer. The elastic member may further comprise means for gripping the cord, such as a rough surface or a series of teeth, to help prevent the cord from slipping.

[0092] The first and / or second mounting portion may form part of the support frame. The first and / or second mounting portion may be formed integrally with the support frame. The second mounting portion may be formed integrally with the support member in a single molding step. Thus, a tab extending planarly across the opening may be formed integrally within the support frame in a single molding step. The tab may protrude from the support frame. Due to manufacturing limitations, flashing may cause the tab to be attached to the opening in an undesirable position, where the distance between the edge of the tab and the adjacent edge of the opening is small, for example, less than 2 mm, or less than 1 mm, or less than 0.5 mm. This can be resolved by applying force to the tab to break the flashing. The force may be applied to the surface of the tab, for example, the surface of the tab protruding from the support frame. Such force may be applied to the tab using an overmolding tool during the overmolding step of forming the sealing member, thus reducing the number of separate steps required in the manufacture of the mask.

[0093] Therefore, a method is provided for integrally forming a tab extending in a planar direction across an opening such that the distance between at least one edge of the tab and at least one adjacent edge of the opening is less than 2 mm, and the method is as follows: a) Using injection molding, form a tab extending planarly across the opening such that the distance between at least one edge of the tab and at least one adjacent edge of the opening is less than 2 mm, b) applying force to the surface of the tab to release the flushing formed between at least one edge of the tab and at least one adjacent edge of the opening during the injection molding process.

[0094] When used in the manufacture of a filter mask, the injection molding process in step a) above can also form a support frame, and the application of force in step b) above can be carried out by designing the shape of the overmolding tool used in the manufacture of the sealing member such that pressure is applied to the tab to break the flushing when the mold is closed on the support member before overmolding. Thus, using this process, the second mounting forming portion of the filter mask described herein can be integrally formed without requiring any additional manufacturing steps.

[0095] Alternatively, the first and / or second mounting portions may be formed separately from the support frame and then connected to the support frame by chemical or mechanical means.

[0096] The mask may have an opening in the filter, which may provide a conduit through the filter, or may include or be adapted to receive a further device such as an exhalation valve. The opening may bypass the filter material. The opening in the filter material may be attached to and / or sealed to an opening in the support frame or to a device attached to the support frame. Furthermore, the polymer material injected into the mold to form the sealing member may be made to engage with the filter and the opening in the support frame or to the device attached to the support frame during injection molding of the sealing member, so as to seal the filter around the opening or device.

[0097] The mask may be provided with one or more vents or valves, such as an exhalation valve. The exhalation valve allows exhaled air to escape from the filter mask without passing through the filter, thus reducing the heat and humidity retained by the filter during use. However, the inclusion of an exhalation valve may be undesirable if the filter mask is required to protect others from pathogens exhaled by the wearer, for example, in a medical setting. The vents or valves may be located within the shield or within the rim of the support frame. The valves may be inserted into an opening in the shield or rim, or may form part of the shield or rim. If the valves are inserted into the shield or form part of the shield, the valves may also extend through the filter material, and an overmolding step forming a sealing member may be used to additionally provide a seal between the valve and the filter material and / or between the opening in the support frame for receiving the valve and the filter material. If the valves are inserted into the rim or form part of the rim, part of the rim may be molded to accommodate the valve, for example, in the jaw area.

[0098] If a valve is included, the injection molding step for forming the sealing member can also form the valve member. Thus, the sealing member and the valve member may be formed integrally. After molding the sealing member / exhalation valve, the valve may be inserted through openings in the filter and shield, or through openings in the rim. The tension between the valve and the surrounding material (shield, filter, or rim) biases the valve to close. This allows exhaled air to flow from the inside to the outside of the mask, but prevents airflow in the opposite direction.

[0099] The support frame, e.g., shield and / or filter, may have an opening into which either a retractable cover or an exhalation valve can be fitted. An overmolding step forming a sealing member may be used to additionally provide a seal between the opening in the support frame for receiving the valve or cover and the filter material. For example, a retractable cover may be secured over the opening using snap-fit ​​or screw-fit connections, and the cover can be removed and replaced with an exhalation valve as needed. This makes it possible to manufacture a single mask that can be used with or without an exhalation valve. The size of the opening may be appropriate for mounting the exhalation valve and may be 10–50 mm in diameter, or 15–40 mm in diameter, or 15–30 mm in diameter. Typically, the diameter of the opening is about 20 mm.

[0100] The filter mask may further include a plug that can be used to connect the mask to a tube for introducing gas to the mask and / or the wearer, or for removing gas from the mask and / or the wearer. Thus, the filter mask may be used as an oxygen delivery mask or a breathing mask with additional protection, such that inhaled air (other than the delivered oxygen) must pass through the filter. In the same manner as the exhalation valve, the plug may be releasably attached to the shield and optionally to the opening of the filter. The opening may be sized to accommodate a plug having a diameter of 10–50 mm, or 15–40 mm, or 15–30 mm. Alternatively, the opening may be sized to accommodate a plug having a diameter of 2–10 mm, or 2–8 mm, or 4–8 mm. Alternatively, the plug may be formed integrally with the shield or another part of the support frame.

[0101] Alternatively, the filter mask may not have a stopper. Such a filter mask would be unsuitable for use as an oxygen delivery mask or breathing mask. The filter mask may additionally or alternatively have an access port. For example, the filter mask may have an access port for an endoscope, nasal cannula, or high-flow nasal cannula, thereby allowing the endoscope to be performed or the cannula to be worn while still providing the protection offered by the filter mask to the patient and physician. A characteristic of this type of treatment is that the drug or oxygen may be delivered through a high-flow nasal cannula, and aerosolized particles may be generated and released into the environment. Depending on the nature of the patient's illness, such aerosolized particles may become contaminated and pose a risk to nearby persons. By allowing access to the airway for delivery of a high-flow nasal cannula, but by wearing a filter mask containing any generated aerosols, a safer environment is provided for clinicians and other nearby personnel. The access port may include an opening within the filter mask. The opening may consist of a pair of openings within a support frame, e.g., a shield, and a sheet of filter material, aligned with each other, through which the cannula can pass. An overmolding step forming a sealing member may be used to provide an additional seal between the opening in the support frame and the filter material. Removable covers may be provided over the openings in the support frame, shield, and / or filter material so as to cover the openings when not in use.

[0102] Alternatively, the face mask may be configured so that the filter material sheet is replaceable. This means that the entire mask does not need to be replaced after use, only the filter material needs to be replaced, while the mask frame, including the support structure and seal, can be reused multiple times. This reduces both costs and waste.

[0103] A mask having a replaceable filter according to this embodiment can be manufactured using the same principles as described above, in a method involving a single overmolding step to fix the relative position of the support frame and the seal.

[0104] A further aspect of the present invention provides a method for manufacturing a filter mask, the filter mask comprising a support frame and a sealing member, the support frame having a housing for receiving a filter, and the method is a) To provide a support frame within the mold, b) Including injecting polymer material into a mold to form a first sealing member for sealing against the wearer's face and a second sealing member for sealing against a filter received by the housing, The sealing member is engaged with the support frame to secure the sealing member to the support frame during injection molding of the sealing member.

[0105] A further aspect of the present invention provides a filter mask manufactured according to the method described above. The filter mask also provides a filter mask comprising a support frame and a sealing member, the support frame further comprising a housing for receiving a filter, and the sealing member being fixed to the support frame. Any of the features described above in relation to the filter mask of the present invention include, but are not limited to, a shield, and / or first and second mounting forming portions, and / or a sealing member having inwardly and outwardly hanging lip portions, and / or inclusion of a valve or access port, which may be present in this embodiment.

[0106] The filter may consist only of a filter substrate, which may be releasably attached to a support frame by any preferred means, for example, by clips, or by interlocking, or by an adhesive strip covered with a releasable adhesive, such as a peelable liner that is removed immediately before insertion of a sheet of filter material.

[0107] Alternatively, the filter may comprise a filter substrate held within a cartridge or other support that can be connected to a support frame. For example, the cartridge may be connected to the outer surface of the support frame by one or more snap-fit ​​connectors or clips, or by friction fitting, or there may be a port provided within the support frame for housing the cartridge. In this embodiment, if the mask comprises a shield, the shield may form part of the cartridge or other support such that the shield is positioned on the outer surface of the filter when the cartridge is attached to the outer surface of the mask (i.e., the cartridge or other support comprises a shield). Alternatively, the shield may be hinged to the support frame and can be opened to allow insertion of a filter cartridge adjacent to the outer surface of the support frame, and then closed. The filter cartridge may be held in place by one or more clips or other mounting members, or a hinged shield may hold the filter cartridge in place.

[0108] Alternatively, the filter cartridge is connected to the inner surface of the support frame by one or more snap-fit ​​connectors or clips. In this embodiment, the shield (if any) may be present as described above, as shown in the drawings. For example, the filter mask may include a shield that, when in use, extends over at least a portion of the outward-facing surface of the filter, with at least a portion of the periphery of the shield being separated from the support frame, and / or a shield that may be formed integrally with the support frame.

[0109] The cartridge may take the form of a plastic rim, such as injection-molded plastic, that matches the shape and size of the filter substrate and is fixed around the periphery of the filter substrate. Therefore, the cartridge does not restrict the airflow through the filter substrate.

[0110] It will be understood that any feature described in relation to one aspect of the present invention may be applied to any other aspect of the present invention. Accordingly, any structural feature described in relation to a mask having an integrated filter, such as a shield, first and second mounting forms, exhalation valve, and / or plug, can be applied to the above-described mask having a replaceable filter.

[0111] Herein, embodiments of the present invention will be described with reference to the following drawings, merely as examples. [Brief explanation of the drawing]

[0112] [Figure 1] This is a perspective view of the support frame in a first embodiment of the filter mask according to the present invention. [Figure 2] Figure 2 is a side view of the support frame. [Figure 3] This is a perspective view of the filter in a first embodiment of the filter mask according to the present invention. [Figure 4a] This is a perspective view of a filter placed within a support frame in a first embodiment of the filter mask according to the present invention, which is currently under manufacture. [Figure 4b] This is the same diagram as Figure 4a without a filter. [Figure 5] This is a perspective view of the core of the mold used in the manufacture of the support frame and filter shown in Figure 4, and the first embodiment of the filter mask according to the present invention. [Figure 6] This is a side view of a first embodiment of the filter mask according to the present invention. [Figure 7] This is a rear perspective view of a first embodiment of the filter mask according to the present invention. [Figure 8] This is a schematic diagram showing the connection between the support frame and the filter material formed by the overmolding of the sealing member. [Figure 9a] This is a front and rear perspective view of a second embodiment of the filter mask according to the present invention. [Figure 9b] This is a front and rear perspective view of a second embodiment of the filter mask according to the present invention. [Figure 10a] This is a front and rear perspective view of a third embodiment of the filter mask according to the present invention. [Figure 10b] This is a front and rear perspective view of a third embodiment of the filter mask according to the present invention. [Modes for carrying out the invention]

[0113] A support frame 10 for use in a filter mask according to the present invention is shown in Figures 1 and 2. The support frame 10 has a generally curved shape and comprises an integrally formed rim 11, a shield 12, a pair of first mounting forming parts 13, and a pair of second mounting forming parts 14. The shield 12 is substantially the same shape as the rim 11, but smaller and offset by about 1 cm from the rim 11. The shield 12 is attached to the rim 11 by four connecting members 16 arranged at equal intervals around the periphery of the rim, and is attached to a point close to the edge of the shield. The space 15 between the shield 12 and the rim 11 extends around the periphery of the shield and is interrupted only by the connecting members 16. The support structure 10 is an integrally formed component, and all features are manufactured in a single injection molding step.

[0114] A pair of first mounting portions 13 extend outward from the first side of the rim 11, which is positioned near the wearer's first ear when in use. The first mounting portions 13 take the form of keyhole-shaped slots through which a cord or strap (not shown) can be passed and secured with a knot or clamping device. A pair of second mounting portions 14 extend outward from the second side of the rim, which is positioned near the wearer's second ear when in use. The second mounting portions 14 include a slot (invisible) covered by a tab 17. The tab 17 has a series of teeth 18 that provide a grip. The cord or strap (not shown) passes through the slot of the mounting portion 14 from the inside to the outside of the support frame between the tab 17 and the edge of the slot. The teeth 18 grip the cord and reduce or prevent the cord from moving in the reverse direction.

[0115] When in use, the cord or strap is secured to the upper first mounting section 13, passes through the upper second mounting section 14 from inside to outside, passes through the lower second mounting section 14 from outside to inside, and is finally secured to the lower first mounting section 13. Thus, the strap passes twice behind the wearer's head, forming a loop between the pair of second mounting sections 14 on the outside of the support structure. When the wearer applies tension to this loop, for example by pulling the loop, the cord is pulled through the opening and passes through the teeth 18 on the tab 17. When this tension is released, for example by the wearer releasing the loop of the cord, the teeth 18 are able to grip the cord, thus preventing the cord from slipping back out of the slot unless a significant force is applied. In this way, the mask can be easily adjusted with one hand to fit the wearer's head.

[0116] Injection molding is used to manufacture the support frame 10, which is a single-piece unit manufactured from polypropylene that is injection-molded in a single step.

[0117] When the manufacture of the filter mask is automated, the support frame 10 is ejected from the mold onto a vacuum cup on a robotic arm. A pneumatic die pushes sheets of filter material 22 from a roll of filter material into the support frame 10, and the roll of filter material contains a continuous series of pre-stamped sheets of filter material which are heat-sealed around their peripheral edges. The sheets of filter material 22 are shown in Figure 3.

[0118] The filter material sheet is positioned inside the support frame 10, i.e., on the side of the support frame 10 that will face the wearer during use. The filter material sheet is positioned on an inwardly extending shoulder portion and is held in place around its periphery by a retaining tab 19 on either side of the rim. This support structure / filter material assembly is shown in Figures 4a and 4b.

[0119] The support structure / filter material assembly is transferred into the first half of the mold and mounted on the mold core 30. The second half of the mold is sealed to the first half of the mold, forming a mold cavity. In the injection molding step, the sealing member 25 is overmolded onto the support structure / filter material assembly, and in a single overmolding step, it surrounds the periphery of the sheet of filter material 22 and adheres it to the support frame 10 to form the sealing member 25. The filter mask 20 is removed from the mold using, for example, a 20 mm pin to peel the filter mask 20 from the core 30, and is transferred for manual attachment of the elastic cord and subsequent packaging.

[0120] Figure 8 schematically shows the connection between the filter, the sealing member, and the support frame. The peripheral portion of the filter 91 is positioned against the shoulder portion 94 that extends laterally from the rim of the support frame 93, either before or after the support frame 93 is placed in the mold. Thermoplastic elastomer (TPE) 92 is injected into the mold to form the sealing member. The portion of TPE 92 shown in Figure 8 represents only the proximal edge of the sealing member. The TPE 92 is pressed by the mold between the peripheral edge of the filter 91 and the rim and shoulder portions of the support frames 93 and 94. The TPE 92 surrounds and impregnates the peripheral edge of the filter 91, and the impregnated area of ​​the peripheral portion, indicated by 95, adheres to the rim and shoulder portions of the support frames 93 and 94. As shown in Figure 8, the tool shutout prevents the TPE 92 from entering the filter 91 beyond the peripheral portion 95, ensuring that the filtering action of the filter 91 is not suppressed by the TPE. In addition to supporting the adhesion of the support frames 93 and 94 to the filter, the impregnation of the peripheral edge 95 of the filter 91 with TPE contributes to the seal at the filter edge formed by heat sealing, preventing moisture or other contaminants from penetrating into the filter structure.

[0121] A side view of the filter mask 20 according to the present invention is shown in Figure 6. The support structure 21 is the same as that described in relation to Figures 1 and 2. The sheet of filter material 22 is positioned behind the support structure 21 and is visible around the periphery of the shield 23 in the gap between the shield 23 and the rim 24. This allows air to flow easily through the shield 23 and through the filter material 22, while still benefiting from the protection of the shield across the filter material.

[0122] The sealing member 25 is overmolded onto the support frame 21 and the filter material 22 to fix their relative positions. The sealing member 25 includes a chin engagement portion 26, a nose engagement portion 27, and a cheek engagement portion 28. The cheek engagement portion 28 extends laterally across the cheek, forming a seal against the softer skin on the cheek and improving the overall seal of the mask.

[0123] The sealing member 25 is formed of an elastomer material. This provides a compressible area between the support structure 21 and the wearer's face, allowing the elastomer material to conform to the contours of the wearer's face and provide a good seal.

[0124] Figures 4a and 4b show the support structure / filter member assembly with and without the filter material, respectively. The support structure 10 comprises a rim 11. The rim 11 has an inwardly extending shoulder 18 on which a pre-cut sheet of the filter material 22 is placed. Extending from the first side of the rim is a first mounting forming portion 13, and a second mounting forming portion 14 extends from the second side of the rim. The support frame 10 also comprises a shield 12. A series of vertical ribs 29 across the rear of the shield 12 ensure that a gap is maintained between the shield 12 and the filter material 22.

[0125] A second embodiment of the filter mask according to the present invention can be seen in Figures 9a and 9b, and is shown overall as 100. The structure of the mask is substantially the same as that described in relation to the first embodiment shown in Figures 6 and 7, except that the mask 100 further comprises a mushroom valve 101 (shown in the closed position). In the jaw region, the rim 102 of the support frame comprises an upward projection 103, and the shapes of the shield 104 and the filter material 105 correspond to the shape of the inner periphery of the rim 102 so that they accommodate the upward projection 103. The filter material 105 is sealed along the periphery of the rim 102 of the support frame, including the upward projection 103, by a peripheral rim of TPE 106. The upward projection comprises an opening, and the mushroom valve 101 is formed within the opening as part of an overmolding step that also forms a sealing member 107. The mushroom valve 101 allows exhaled air to escape without passing through the filter material 105. Alternatively, the mushroom valve 101 can be housed within the shield 104.

[0126] A third embodiment of the filter mask shown in Figures 10a and 10b is shown overall as 110 and has substantially the same structure as that described in the second embodiment in relation to Figures 9a and 9b, but with an elbow connector 111 instead of a mushroom valve. The elbow connector 111 allows the mask 110 to be connected to other medical devices such as a nebulizer.

Claims

1. A filter mask comprising a support frame, a filter, and a sealing member, wherein the support frame holds the filter so that ambient air is drawn through the filter when the wearer inhales, and the support frame includes a shield extending over at least a portion of the outward-facing surface of the filter, the shield being separated from the filter, and air flowing between the shield and the filter during use.

2. The filter mask according to claim 1, wherein the support frame comprises a rim and a shield, and the shield is offset from the rim.

3. The filter mask according to claim 2, wherein the rim extends around and / or onto the peripheral portion of the filter, and the shield is offset from both the rim and the filter.

4. The filter mask according to claim 2 or 3, wherein the rim and the shield are connected together by one or more connecting members that extend between the shield and the rim and fix their relative positions.

5. The filter mask according to any one of claims 1 to 4, wherein the shield has a shape corresponding to the shape of the filter, and the surfaces of the filter and the shield are parallel.

6. The filter mask according to any one of claims 1 to 5, wherein, when measured along a line perpendicular to the surface of the shield, there exists a gap between the shield and the filter having an average size of 0.1 to 5 cm, or 0.2 to 2.5 cm, or 0.2 to 1.5 cm, or 0.3 to 1 cm.

7. A filter mask according to any one of claims 1 to 6, wherein one or more ribs are provided extending over at least a portion of the surface of the shield facing the filter, and the ribs are in contact with the filter.

8. The filter mask according to any one of claims 1 to 7, wherein the surface area of ​​the shield is at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% of the surface area of ​​the filter.

9. The filter mask according to any one of claims 1 to 8, wherein the shield extends over less than 100% of the surface area of ​​the filter, and a portion of the filter is exposed at the periphery of the shield.

10. The filter mask according to any one of claims 1 to 9, wherein the shield does not have an opening formed internally through which a sheet of the filter material is exposed, and forms a continuous barrier.

11. A filter mask comprising a support frame, a filter, and a sealing member, wherein the support frame holds the filter so that ambient air is drawn through the filter when the wearer inhales, and the support frame includes a shield extending over at least a portion of the outward-facing surface of the filter, with at least a portion of the periphery of the shield separated from the support frame, and one or more inlet openings defined between the shield and the support frame through which air is drawn when the wearer inhales.

12. The filter mask according to claim 11, wherein the separation between the peripheral portion of the shield and the support frame is less than 2 cm, or less than 1.5 cm, or less than 1 cm.

13. The filter mask according to claim 11 or 12, wherein the shield forms a continuous barrier, and the one or more inlet openings are arranged around the peripheral portion of the shield.

14. The filter mask according to any one of claims 11 to 13, wherein one or more inlet openings in the nasal and / or chin region extend outward along a curved path from an angled apex in the central region of the mask toward the side of the mask so as to receive the wearer's fingers during a fit test, the fingers meeting at the angled apex.

15. The filter mask according to any one of claims 11 to 14, wherein the filter mask is provided with covers for one or more inlet openings, the covers enabling the inlet openings to be closed in order to perform a fit test.

Images