Patent Publication Number: US-2023158344-A1

Title: Breathing mask with particle filter

Description:
Particle-filtering half masks are used as respiratory protection against aerosols made up of solid or liquid, not highly volatile particles. They are tested according to European Standard DIN EN 149 and meet the requirements of this standard. The standard distinguishes the device classes FFP1, FFP2, and FFP3 depending on the retention capacity of the particle filter. The mask typically consists completely of the nonreplaceable filter material. Examples of such masks are disclosed in DE 10 2014 221 311 B3 and DE 20 2013 011 420 U1. 
     It is necessary to draw a distinction between the above and “half masks or full masks with a particle filter”, which have one or more attachment options for replaceable particle filters. Half masks or full masks with replaceable particle filters according to DE 10 2014 001 937 B3 or DE 20 2014 001 315 U1 are presently quite bulky masks, which are used in particular in the industrial sector and greatly restrict the field of view. Moreover, such masks have at least one valve for inhalation and/or exhalation. 
     The leak-tightness is decisive for the protective effect of a breathing mask. This results from the filter penetration and the so-called fitting leakage, which arises due to leaks between the sealing line of the mask and the face of the wearer. The protective effect increases from an FFP1 mask (total leakage maximum 22%) via an FFP2 mask (total leakage maximum 8%) to the FFP3 mask (total leakage maximum 2%). The breathing resistance of the mask also rises with the increase in the protective effect. The exhalation resistance is reduced by an exhalation valve. The particle-filtering half mask is thus less burdensome for the wearer and is therefore preferably to be used. 
     In addition to the filter properties, above all the seal seat of the mask is decisive for the effectiveness of the mask. The specified values with respect to the protective effect only apply for an optimum seat, which is only achieved by careful, correct placement. In general, wearing a well-fitted FFP2 mask represents suitable protection from infectious aerosols, including viruses, since it can be presumed that they are bound to ultrasmall droplets and are thus captured in the filter. 
     FFP masks are disposable articles and have to be discarded correctly after use for hygienic reasons. When removing the FFP mask, it is to be ensured that the outer surface of the FFP mask does not come into contact with mouth, nose, mucosae, or unprotected hands. Protective gloves are to be replaced immediately after removing the FFP mask and the hands are to be disinfected. 
     The breathing masks according to the prior art have the following significant disadvantages:
         Half or full masks primarily from the industrial sector have bulky constructions and are rather cumbersome to handle, in particular for the filter changing, moreover the production is complicated and expensive.   The FFP masks conceived as disposable articles produce a large quantity of waste to be handled separately.   The masks are conceived as standard sizes or in standard forms with little adaptability. In particular in the case of distinctive facial contours, a tight seat on the face of the user thus cannot be ensured, so that a high level of leakage can result and secure filtering of the respiratory air does not take place.   The breathing masks according to the prior art have an exhalation valve, which is to facilitate the exhalation by the user. This has the disadvantage that, although the user is protected from possible infectious aerosols in the surroundings, if the user himself discharges bacteria or other infectious microorganisms via the respiratory air, these are exhaled unfiltered into the surroundings.       

     The object of the invention is to provide a breathing mask which, on the one hand, fits on many facial shapes and seals with little leakage, also enables filtering of the exhaled respiratory gas, and has a filter which is easy to change. This object is achieved according to the invention by the proposed breathing mask having the features of claim  1  and the optional filter element having the features of claim  38 . 
     The subject matter of the present invention is a breathing mask, comprising a mask body, a mask bead, at least one strap holder, and at least one filter device, wherein the mask bead, the at least one strap holder, and the at least one filter device are connected to the mask body and/or are part of the mask body, wherein the breathing mask fully encloses the nose and mouth of the user, wherein the mask bead partially delimits a receptacle opening for the nose and mouth of the user. The at least one filter device comprises at least one filter receptacle and at least one filter element here. The mask bead has a contact region embodied as a sealing lip and is conFig.d so that the breathing mask presses against the facial skin around at least the nose and mouth of the user with the sealing lip during use and provides a seal in an essentially respiratory-gas-tight manner. For this purpose, the filter device is at least partially replaceable, and respiratory gas can at least partially flow through it, wherein the filter element comprises at least one filter material. 
     In some embodiments of the breathing mask, the mask body, the filter receptacle, and the mask bead define a respiratory gas chamber, which is essentially respiratory-gas-tight during use and thus a respiratory gas flow from and/or to the mouth and nose of the user is possible exclusively through the filter device. 
     In some embodiments of the breathing mask, the mask bead comprises a nasal bridge region, a base region, two side regions, a mask fitting, and a contact region, wherein the nasal bridge region and the base region are spatially separated from one another by the side regions and the nasal bridge region and the base region are each connected to both side regions. Because the two side regions cannot be directly connected to one another and nor can the base region be directly connected to the nasal bridge region, two openings thus result in the mask bead. One of these openings represents the receptacle opening for the mouth and nose of the user. The other opening accordingly faces in the direction of the mask body. Depending on the face of the user, in particular with respect to the size of the nose, the breathing mask can be embodied so that, for example, the nose of the user protrudes into the space of the mask body. 
     In some embodiments of the breathing mask, the sealing lip describes a curve in cross section starting from the side regions, the nasal bridge region, and the base region and the edge of the sealing lip essentially determines the size of the area of the receptacle opening. 
     In some embodiments of the breathing mask, the wall thickness in the region of the side regions is greater than the wall thickness of the sealing lip. However, it is also possible that the sealing lip has the same wall thickness as the side regions of the mask bead. 
     In some embodiments of the breathing mask, the wall thickness of the mask bead decreases continuously from the side regions to the sealing lip. Within the sealing lip, the wall thickness can decrease further, for example to reach the lowest wall thickness at the edge of the sealing lip. On the other hand, however, it can also be possible that the wall thickness increases again within the sealing lip. 
     In some embodiments of the breathing mask, the wall thickness of the mask bead is less in the nasal bridge region and base region than in the side regions, wherein the wall thickness increases in the base region toward the side regions, so that a transition region results, which is arranged at least partially in the base region, wherein the wall thickness in the nasal bridge region and the base region at least corresponds to the wall thickness of the sealing lip. This is also to be understood to mean that the wall thickness can decrease from the base region or the nasal bridge region to the sealing lip. Thus, for example, the side regions could have the greatest wall thickness, the nasal bridge region and the base region could have a lesser wall thickness in relation thereto, wherein the sealing lip has the lowest wall thickness. For example, it is also possible that the wall thickness of the sealing lip is greater or less in the regions starting from the side regions than in the regions starting from the nasal bridge region or the base region. 
     In some embodiments of the breathing mask, the contact region of the mask bead has corner points at the transitions from the nasal bridge region to the side region and from the base region to the side region, which are used for the alignment of the breathing mask on the face. For this purpose, these corner points have, for example, a higher wall thickness at least at points, which can partially also be greater than the wall thickness of the side regions. These corner points can also be formed, for example, as regions at the transitions between side region and nasal bridge region or base region. 
     In some embodiments of the breathing mask, the sealing lip protrudes starting from the side regions, the nasal bridge region, and the base region in an arc into the receptacle opening of the mask bead. 
     In some embodiments of the breathing mask, the filter receptacle is formed as a surface, thus has a significantly greater extension in a direction x 2  and a direction y 2  perpendicular thereto than in a direction z 2  perpendicular to the plane E 2  spanned by x 2  and y 2 . For example, the ratio between extension in the direction z 2  and the extension in the direction y 2  or x 2  is at least 1:10. 
     In some embodiments of the breathing mask, the ratio of the area of the receptacle opening of the breathing mask to the area of the filter device through which flow occurs is between 2:1 and 1:2, wherein the area of the filter device through which respiratory gas flows is at least 16 cm 2 . If more than one filter device is provided, the area of the filter device through which flow occurs thus relates to the entire area through which flow occurs, thus the sum of the areas through which flow occurs of all provided filter devices. If, for example, two filter devices having equal area through which flow occurs are provided, the area through which flow occurs of a filter device is to be at least 8 cm 2 , so that in total at least 16 cm 2  of area through which flow occurs are provided. 
     In some embodiments of the breathing mask, the respiratory gas chamber and the filter device are at least dimensioned so that it is possible to wash out CO2. The respiratory gas chamber is dimensioned, for example, so that it has a volume of 180 ml to 500 ml. 
     In some embodiments of the breathing mask, the filter device is arranged so that a substantially unobstructed flow is enabled between mouth/nose and filter device. The respiratory gas flow should thus have the most direct possible path between mouth/nose and filter device or through the filter device. 
     In some embodiments of the breathing mask, the filter receptacle defines a plane E 2  and the mask bead defines a plane E 1 , wherein the mask bead is constructed essentially mirror-symmetrically. The mirror plane E 3  extends here through the base region and the nasal bridge region, but not through the side regions. The plane E 1  intersects the mirror plane E 3  and is spanned by at least two connecting lines (L 1 , L 2 ), wherein the connecting lines (L 1 , L 2 ) each extend between a point (p 1 , p 2 ) on the outside of the contact region facing toward the face of the user and the associated mirror point (p 1 ′, p 2 ′). 
     In some embodiments of the breathing mask, the planes E 1  and E 2  extend in parallel to one another and are spaced apart from one another. 
     In some embodiments of the breathing mask, the planes E 1  and E 2  extend perpendicularly to the mirror plane E 3 . 
     In some embodiments of the breathing mask, the plane E 1  is perpendicular to the mirror plane E 3  and the plane E 2  extends inclined at an angle of 0° to 15° in relation to the plane E 1  and/or the mirror plane E 3 . 
     In some embodiments of the breathing mask, the planes E 1  and E 2  are perpendicular or inclined at an angle between 90° and 45° in relation to one another. 
     In some embodiments of the breathing mask, the filter material is conFig.d and formed to filter germs (e.g., viruses, bacteria, fungi) and other microorganisms out of the air and/or other gases and retain them on and/or in the filter material. Moreover, it is possible, for example, that the filter material consists of a material which can be easily reprocessed after use, without then having restrictions in the functionality. 
     In some embodiments of the breathing mask, the filter material essentially consists of plastic fibers. 
     In some embodiments of the breathing mask, the filter material essentially consists of polypropylene. 
     In some embodiments of the breathing mask, the filter receptacle encloses the outer edges of the filter element in a respiratory-gas-tight manner. 
     In some embodiments of the breathing mask, the filter receptacle accommodates the filter element in such a way that a respiratory gas flow through the filter device is possible exclusively through the filter material ( 401 ) contained in the filter element. 
     In some embodiments of the breathing mask, the filter element comprises at least one filter frame, wherein the filter material is clamped or pinched in the filter frame or is connected to the filter frame. 
     In some embodiments of the breathing mask, at least one locking device is arranged on the filter frame, wherein the locking device is formed as a locking projection and/or as a locking recess. This locking device can be used, for example, to lock the filter element in the filter receptacle, thus, on the one hand, to align it, but also, for example, to secure the filter element against slipping or falling out of the filter receptacle. 
     In some embodiments of the breathing mask, the filter receptacle comprises a filter receptacle base and optionally a filter holder. 
     In some embodiments of the breathing mask, the filter receptacle base and the filter holder have a screw thread by which the filter receptacle base and the filter holder are connected to one another. 
     In some embodiments of the breathing mask, the filter receptacle is connected in a respiratory-gas-tight manner to the mask body or is part of the mask body. A respiratory-gas-tight connection between mask body and filter receptacle can be produced, for example, in that the mask body is manufactured from an elastomeric material and has an undercut or a recess into which the filter receptacle or at least the filter receptacle base can be pressed. The recess would have to completely enclose and abut the edges of the filter receptacle for this purpose, so that a respiratory-gas-tight connection results. Alternatively, it is also possible to adhesively bond the filter receptacle or at least the filter receptacle base in the mask body. 
     In some embodiments of the breathing mask, the mask body is manufactured integrally with the mask bead and the strap holder. 
     In some embodiments of the breathing mask, the filter receptacle is connected to the mask body by extrusion coating. In some embodiments of the breathing mask, the filter receptacle is also manufactured integrally with the mask body, the mask bead, and the strap holder. 
     In some embodiments of the breathing mask, the strap holder is formed and conFig.d to accommodate at least one head fastening strap. 
     In some embodiments of the breathing mask, the strap holder is formed as a fastening projection protruding from the mask body, wherein feedthrough openings for feeding through the head fastening strap are arranged in the fastening projection. 
     In some embodiments of the breathing mask, the feedthrough openings taper at least partially in a funnel shape or conically. 
     In some embodiments of the breathing mask, the head fastening strap is manufactured integrally with the strap holder and is optionally formed as a loop. 
     In some embodiments of the breathing mask, the mask body, the strap holder, and/or the filter receptacle is produced from a dimensionally stable plastic. 
     In some embodiments of the breathing mask, the mask body, the strap holder, and/or the filter receptacle is produced from an elastomeric plastic. 
     In some embodiments of the breathing mask, the mask body, the strap holder, and/or the filter receptacle is produced from a polycarbonate, a polyamide, a polypropylene, a polyoxymethylene, or a silicone. It is not necessarily required here for the individual components to be produced from the same materials. For example, the mask body together with the strap holder can be produced from a silicone and the filter receptacle can be produced from another material. 
     In some embodiments of the breathing mask, the mask bead is produced from silicone. 
     In some embodiments of the breathing mask, the strap holder is produced from the same material as the mask body. 
     In some embodiments of the breathing mask, the filter receptacle is produced from the same material as the mask body. 
     In some embodiments of the breathing mask, the filter receptacle is produced from a dimensionally stable plastic and the mask body is produced from an elastomeric plastic. 
     In some embodiments of the breathing mask, the head fastening strap is an elastic strap. 
     In some embodiments of the breathing mask, the mask body is produced integrally with the mask bead, the strap holder, and the filter receptacle. 
     In some embodiments of the breathing mask, the breathing mask is constructed and produced from one or more materials in such a way that the breathing mask, optionally without filter element, can be cleaned in a germicidal manner. The breathing mask is to remain as undamaged as possible in this case, that is to say at least is not to suffer any damage influencing the functionality, for example due to partial degradation/dissolving of the breathing mask. Methods for germicidal cleaning are, for example, autoclaving, washing, dry heating, or spraying on a disinfectant. 
     In some embodiments of the breathing mask, the filter receptacle and the filter element are configured and adapted to one another in such a way that it is possible to change the filter element while wearing the breathing mask, wherein exclusively the filter element has to be touched by the extremities of the user or another person. For example, only the filter element comes into contact with a hand of the user or another person. The breathing mask itself would nonetheless continue to rest respiratory-gas-tight on the face of the user in this case due to the head fastening strap and the strap holder. 
     In some embodiments, the filter element can be removed from the filter receptacle and/or inserted into the filter receptacle with a hand movement. Such a hand movement can be, for example, pulling on a handle on the filter element or a screwing movement. 
     In some embodiments of the breathing mask, at least one pressing edge is formed on the filter receptacle base, onto which the filter material is pressed by the filter holder. 
     In some embodiments of the breathing mask, at least one holding tip is formed or arranged on the filter receptacle webs of the filter receptacle base. 
     In some embodiments of the breathing mask, at least one mounting projection is formed on the filter receptacle base and a recess is formed in the mask body to accommodate this mounting projection. 
     In some embodiments of the breathing mask, at least one pressing edge is formed on the filter holder, which presses on the filter material and/or at least partially fixes and/or clamps it on the filter receptacle base. 
     In some embodiments of the breathing mask, at least one mounting projection is formed on the filter holder and at least one groove is formed in the mask body to accommodate the at least one mounting projection. 
     In some embodiments of the breathing mask, the locking device at least partially consists of a tab on the filter holder, wherein the tab, together with the filter holder edge, forms at least one locking recess for accommodating at least one locking projection. 
     In some embodiments of the breathing mask, at least one mounting opening is arranged in the mask body, which is designed for feeding through and holding the at least one locking projection of the filter receptacle base. 
     The invention is described hereinafter in the form of exemplary embodiments of the invention on the basis of illustrations, some of which are greatly simplified. 
    
    
     
         FIG.  1    schematic illustration of a breathing mask in a side view. 
         FIG.  2    schematic illustration of a breathing mask having two filter devices in a top view. 
         FIG.  3    perspective illustration of a mask body with filter receptacle. 
         FIG.  4    schematic illustration of a mask body with filter receptacle in a front view. 
         FIG.  5    perspective illustration of a mask bead. 
         FIG.  6   a    schematic side view of a mask bead. 
         FIG.  6   b    schematic illustration of the course of a sealing lip. 
         FIG.  7    schematic illustration of a mask bead in a front view. 
         FIG.  8   a    schematic illustration of a mask bead in a top view. 
         FIG.  8   b    schematic illustration of a mask bead in a side view. 
         FIG.  9    schematic illustration of a filter receptacle in a perspective view. 
         FIG.  10    perspective illustration of a filter holder. 
         FIG.  11    perspective illustration of a filter element. 
         FIG.  12   a    schematic front view of a filter element. 
         FIG.  12   b    schematic cross section through a filter element. 
         FIG.  13   a    schematic illustration of a filter receptacle base and a filter holder. 
         FIG.  13   b    schematic illustration of a filter receptacle base and a filter holder. 
         FIG.  14   a    schematic illustration of a filter holder. 
         FIG.  14   b    schematic illustration of a filter holder. 
         FIG.  14   c    perspective illustration of a filter holder. 
         FIG.  14   d    perspective illustration of a filter holder. 
         FIG.  15   a    schematic illustration of a filter receptacle base. 
         FIG.  15   b    schematic illustration of a filter receptacle base. 
         FIG.  15   c    schematic illustration of a filter receptacle base. 
         FIG.  15   d    detail D 1  from  FIG.  15     c.    
         FIG.  16   a    side view of a filter receptacle base. 
         FIG.  16   b    detail D 2  from  FIG.  16     a.    
         FIG.  17   a    detail/cross section from the mask bead. 
         FIG.  17   b    detail/cross section from the mask bead. 
         FIG.  18   a    one-piece mask body with mask bead in perspective. 
         FIG.  18   b    one-piece mask body with mask bead in a front view. 
         FIG.  18   c    one-piece mask body with mask bead in a side view. 
         FIG.  19   a    perspective view of a breathing mask. 
         FIG.  19   b    detail view of locking. 
         FIG.  20    exploded view breathing mask. 
         FIG.  21    detail strap. 
         FIG.  22   a    holding clip for a strap. 
         FIG.  22   b    holding clip for a strap. 
     
    
    
       FIG.  1    shows a greatly simplified, schematic illustration of an exemplary embodiment of the breathing mask  1  in a side view. The breathing mask  1  comprises here a mask body  2 , a mask bead  3 , a filter device  4 , and a strap holder  5 . The general direction toward the user is indicated by the arrow identified by A, the mask bead  3  thus faces here in the direction toward the user. The mask bead  3 , the filter device  4 , and the strap holder  5  are connected to the mask body. In one exemplary embodiment, the mask body  2  is produced integrally together with the strap holder  5 , while the mask bead  3  and the filter device  4  are produced separately and are connected later to the mask body. The mask bead  3  can be plugged onto the mask body  2 , for example, via the mask fitting  35  (not shown in greater detail in  FIG.  1   ), which results in a reversible bond between mask body  2  and mask bead  3 . A permanent connection by, for example, adhesive bonding, extrusion coating, or other connection methods is also possible. 
     The strap holder  5  can be, for example, a fastening projection  50 , which is provided with at least one feedthrough opening  51 , through which a head fastening strap  52  (not shown) can be guided and is, for example, knotted behind it, so that a solid seat of the breathing mask  1  on the face of the user is ensured. If the feedthrough opening  51  is made conical or funnel-shaped, for example, wherein the feedthrough opening  51  is arranged tapering in the direction away from the user, but not closing, knotting of the head fastening strap  52  is possibly not necessary since, although easy threading is enabled by the funnel shape, on the other hand the opposite pulling direction is blocked or at least made much more difficult. Alternatively, the strap holder  5  is designed, for example, as a type of lashing eye, through which the head fastening strap  52  can be guided. For example, the head fastening strap  52  is equipped for this purpose with a hook-and-loop closure, so that a length adjustment is possible. In other and further exemplary embodiments, the head fastening strap  52  is an elastic strap, which is guided in a stretched state over or behind the head of the user and then in a less stretched state presses the breathing mask  1  lightly against the face of the user in order to seal it in a respiratory-gas-tight manner with respect to the face. 
       FIG.  2    shows a simplified schematic illustration of an exemplary embodiment of a breathing mask  1  according to the invention in a top view, wherein two filter devices  4  are arranged on the breathing mask. The planes E 1  and E 2  are indicated as examples in  FIG.  2   , wherein the plane E 2  extends through the filter device and the plane E 1  extends along the contact region  34  of the mask bead  3 . The filter devices  4  are arranged so that the plane E 2  extending through the filter device  4  extends at an angle between 45° and 90° in relation to the plane E 1  extending on the contact region  34  and intersects it. 
       FIG.  3    shows an exemplary embodiment of a mask body  2  of the breathing mask  1  in a perspective view. The filter receptacle  41  or the filter receptacle base  411  is produced integrally with the mask body  2 . The filter receptacle base  411  is, for example, round and has a filter receptacle lug  413  in the center, on which a filter element  40  can be aligned and which is connected via webs  414  to the filter receptacle edge  415  of the filter receptacle base  411 . A filter receptacle opening  416  is defined by the filter receptacle edge  415 , through which filter receptacle opening  416  the respiratory gas can flow out of the respiratory gas chamber into or through the filter element  40  and can flow from the filter element  40  into the respiratory gas chamber. For example, the filter element  40  can be laid on the filter receptacle base  411  and then solidly clamped using a filter holder  412  (not shown in  FIG.  3   ) in the filter receptacle  41 . The webs  414  and the filter receptacle edge  415  are designed for this purpose in such a way that the filter element  40  can rest thereon and cannot be pressed—at least inadvertently—through the filter receptacle base  411  into the respiratory gas chamber of the breathing mask  1 . The filter element  40  is to be embodied here, for example, in such a way that the diameter of the filter element  40  corresponds to the internal diameter of the filter receptacle base  411 . For easy positioning inside the filter receptacle  41 , for example, a positioning hole  4011  corresponding to the filter receptacle lug  413  is arranged in the filter element  40 . Moreover, locking projections  4021  are attached by way of example to the filter receptacle base  411 . The filter holder  412  can be locked on these locking projections  4021 , for example. For this purpose, the filter holder  412  would have corresponding locking recesses  4022 . In a further exemplary embodiment of the breathing mask  1 , the filter receptacle base  411  has a screw thread  403 , so that the filter element  40  or the filter holder  412  can be screwed together with the filter receptacle base  411 . The round shape of the filter receptacle base  411  is to be viewed as an example, i.e., the shape can also be embodied as a rectangle or polygon or as free form. In this case, the filter holder  412  and the filter element  40  would also have to be adapted in their shape to the filter receptacle base  411 , so that a respiratory-gas-tight seat can be achieved. 
     Strap holders  5  are attached in the upper region of the exemplary mask body  2  and in the side region of the mask body  2 . The strap holders  5  are embodied, for example, as a type of lashing eye, through which the head fastening strap  52  can be guided. An exemplary embodiment of a head fastening strap  52  has, for example, a hook-and-loop closure, thus regions which are provided with small barbs and regions which are provided with, for example, a fleece. Such an exemplary head fastening strap  52  can represent a simple option for adjusting the length of the head fastening strap  52  to the head shape of the user in order to achieve a comfortable and secure seat of the breathing mask  1 . 
     Furthermore, a mask fitting  35  is shown in  FIG.  3   , which enables, for example, a reversible connection to a mask bead  3 . A mask bead  3  can be plugged onto the mask fitting  35 , for example. A permanent connection of the mask bead  3  to the mask body  2  by, for example, adhesive bonding or extrusion coating would also be possible at this point. 
     The exemplary embodiment of the mask body  2  shown in  FIG.  3    is manufactured, for example, from a dimensionally stable plastic. Manufacturing from an elastomeric material is also possible. 
     In particular if the mask body  2  is manufactured from a dimensionally stable plastic, the mask bead  3  is manufactured separately and connected later to the mask body  2 . 
     In a further exemplary embodiment of the breathing mask  1 , the mask body  2  is integrally produced together with the filter receptacle base  411  from an elastomeric material. The filter receptacle base  411  can be embodied here in such a way that it is at most as large, for example, is slightly smaller than the filter element  40  and is provided without locking device. The filter element  40  can then be pressed into the filter receptacle base  411  and pulled out again for a change. For this purpose, it is advantageous if the filter element  40  also has, in addition to the filter material  401 , a filter frame  42 , which again has sufficient stability so that the filter element  40  can be inserted securely into the filter receptacle base  411 . 
       FIG.  4    shows a greatly simplified illustration of an exemplary embodiment of the breathing mask  1  having a filter device  4  in a front view. The filter device  4  is arranged here as in the exemplary embodiment in  FIG.  3   . In contrast to  FIG.  3   , the strap holder  5  is embodied, for example, as a fastening projection  50  having two feedthrough openings  51  for in each case at least one head fastening strap  52 . An elastic strap can be guided as a head fastening strap  52  through the feedthrough openings  51 , for example, which is guided behind the head of the user to achieve a solid seat of the breathing mask  1  on the face, at least in the region around the nose and the mouth. To prevent loosening of the seat or slipping of the head fastening strap  52  out of the strap holder  5 , the ends of the head fastening strap  52  are knotted, for example, on the side of the strap holder  5  facing away from the user. In the schematically shown exemplary embodiment of the strap holder  5  having two feedthrough openings  51  in each case, for example, a total of two head fastening straps  52  are threaded through the strap holder  5 . For example, the one head fastening strap  52  is guided between the respective upper feedthrough openings  51  and the second head fastening strap  52  is guided through the respective lower feedthrough openings  51 . 
     For example, the feedthrough openings  51  are tapering conically or in a funnel shape opposite to the direction toward the user. With feedthrough openings  51  shaped in such a way, knotting of the ends of the head fastening strap  52  can possibly be omitted, since the funnel-shaped feedthrough openings  51  permit easy feeding through of the strap in the direction in which the feedthrough openings  51  taper. Against the tapering direction of the feedthrough opening  51 , in contrast, the movement of a strap is blocked or at least strongly obstructed. For this purpose, it is advantageous if the head fastening strap  52  used has, for example, a somewhat larger cross section, independently of the shape, than the smallest cross section of the feedthrough opening  51 . 
       FIG.  5    shows a perspective illustration of an exemplary mask bead  3  for a breathing mask  1  according to the invention. The mask bead  3  delimits the receptacle opening  20  to the sides by way of two side regions  31 , a base region  32 , and a nasal bridge region  33 . The area of the receptacle opening  30  is determined in the direction A toward the user by the edge  342  of the contact region  34  embodied as a sealing lip  341 . The contact region  34  simultaneously represents the front boundary, i.e., the side facing toward the user, of the receptacle opening  30  by the mask bead  3 . The mask fitting  35  forms the transition to the mask body  2  in the “rear”, i.e., the side of the mask bead  3  facing away from the user. The receptacle opening  30  is designed for this purpose to enclose at least the nose and mouth of the user, wherein the mask bead  3  presses via the sealing lip  341  in a respiratory-gas-tight manner against the face of the user and forms a seal. In the mask bead shown as an example in  FIG.  5   , the corner points  311 ,  312 ,  313 , and  314  are additionally formed, which are solidified in relation to the remaining mask bead or have an increased wall thickness, for example. These corner points are arranged, for example, in such a way that they rest on less sensitive points in the face of the user and thus additionally support the mask bead and are additionally also used for the alignment of the breathing mask  1 . The supporting function of these corner points also enables, for example, other regions of the mask bead  3  to be embodied having a lesser wall thickness. The mask bead  3  can thus have a significantly lower wall thickness in the nasal bridge region  33 , for example, which has the result that in this region the mask bead is not supported with respect to the face and is configured to be more flexible. The mask bead  3  or the sealing lip  341  can thus more easily adapt itself in this region to the facial contour and at the same time does not exert additional pressure in the sensitive region of the nasal bridge of the user. In addition to the lesser wall thickness, a notch  343  is also arranged in the nasal bridge region  33  in the exemplary mask bead  3 , which additionally enables easier adaptation to the facial contours of the user. 
     The mask bead  3  is manufactured, for example, from an elastomeric material either integrally with the mask body  2  (and optionally the filter receptacle  41  and/or the strap holder  5 ) or is provided separately and is connected to the mask body  2  for use. In the case of integral production with at least the mask body  2 , the mask fitting  35  of the mask bead  3  merges, for example, continuously into the mask fitting  35  of the mask body  2 . Sharp positioning of the respective mask fittings would thus possibly no longer be able to be made out and is to be understood here as a transition region between mask bead  3  and mask body  2 . In the case of separate manufacturing of the mask bead  3 , for example, if the mask body  2  is provided from a dimensionally stable plastic, the mask fitting  35  of the mask bead is configured and designed, for example, so that it can be plugged in a respiratory-gas-tight manner onto the mask body. Alternatively, a permanent connection between mask bead  3  and mask body  2  would also be possible if the two are manufactured separately. This connection can be carried out, for example, by extrusion coating, adhesive bonding, or welding or another permanent connection technology. 
     The shape shown of the mask bead  3  is to be understood as an exemplary embodiment of a mask bead  3  for the breathing mask  1  according to the invention. In particular in the region of the contour of the sealing lip  341  or the contact region  34 , the mask bead can vary. Variations in the region of the mask fitting  35  are also comprised by the invention, wherein the contour and embodiment of the mask fitting  35  is advantageously embodied as matching with the mask body  3  or the mask fitting  35  therein. 
     A further, greatly simplified sketch of an exemplary embodiment of the mask bead  3  is shown in  FIG.  6   a    in a side view. The mirror plane E 3  shown extends in the mask bead  3  through the base region  32  and the nasal bridge region  33  without intersecting the side region  31 . The two points p 1  and p 2  are marked as examples on the outer side of the contact region  34 , thus the side facing toward the user. The plane E 1  rests on the points p 1 , p 2 . The plane E 1  is defined by connecting lines L 1 , L 2  extending in parallel, which extend between the points p 1 , p 2  and their mirror points p 1 ′, p 2 ′, as is further illustrated as shown in  FIGS.  7  and  8   . The points p 1 , p 2  can be selected arbitrarily here on the outer side of the contact region  34  facing toward the user. For example, the points p 1 , p 2  are selected so that they lie on the outermost points on the side of the mask bead  3  facing toward the user, as schematically indicated in  FIG.  6     a.    
     The contact region  34  of the mask bead  3  is embodied, for example, as a sealing lip  341 . The sealing lip  341  protrudes, for example, starting from the side region  31 , the base region  32 , and the nasal bridge region  33  in an arc into the receptacle opening  30 . Various cross sections of the sealing lip  341  are outlined by way of example and greatly simplified in  FIGS.  6     b, c, d . An exemplary cross section is shown in  FIG.  6   b   , in which the wall thickness decreases continuously from the side region  31  in the direction of the sealing lip  341 . In the sealing lip  341 , the wall thickness decreases further in the direction of the edge  342 . The cross section of the sealing lip  341  describes an arc here, so that the edge protrudes with a length into the receptacle opening  30 . The part of the sealing lip  341  protruding into the receptacle opening  30  is perpendicular to the side region  31  here. The edge  342  of the sealing lip defines the area of the receptacle opening  30 . The part of the sealing lip protruding essentially perpendicularly into the receptacle opening moreover also represents a surface which rests on the face of the user. 
       FIG.  6   c    shows an exemplary cross section of the side region  31  and of the sealing lip  341 , wherein the sealing lip folds over in an arc starting from the side region  31  into the receptacle opening, so that the edge points within the receptacle opening in the direction opposite to the user. As also in the course described in  FIG.  6   b   , a section of the sealing lip  341  extending perpendicularly to the side region  31  thus also results, which forms, for example, a contact surface on the face of the user. The wall thickness of the mask bead takes a similar course here as described for  FIG.  6   b   —decreasing from the side region  31  into the sealing lip  341 , wherein the wall thickness in the sealing lip  341  decreases further to the edge  342 . 
     A further exemplary embodiment of the mask bead  3  is outlined in simplified form in  FIG.  6   d   . The wall thickness decreases in the side region  31  toward the sealing lip  341  and decreases further within the sealing lip  341  toward the edge  342 . The course of the cross section of the sealing lip  341  describes a small arc here, so that the edge  342  only protrudes slightly into the receptacle opening  30 . In contrast to the exemplary embodiments described in  FIG.  6   b, c   , a surface perpendicular to the side region  31  does not result here, at least without contact on the face of the user. Upon contact, however, it is conceivable that the sealing lip  341  or the edge  342  is pressed further into the receptacle opening  30  and the sealing lip at least partially rests flatly on the face of the user. 
     In the exemplary embodiments of the mask bead  3  in  FIGS.  6     b, c, d , the wall thickness decreases starting from the side region  31  via the sealing lip  341  to the edge  342  of the sealing lip. The wall thickness of the sealing lip  341  can also, however, remain continuous, for example, already from the transition from the side region  31 . A continuous wall thickness from side region  31  to edge  342  of the sealing lip  341  is also possible. The course of the wall thickness can also vary for this purpose depending on the point in the mask bead. The wall thickness can thus be continuously uniform in the region of the corner points ( 311 ,  312 ,  313 ,  314 ), while the wall thickness decreases in the base region  32  toward the edge  342  of the sealing lip  341 . It is also possible that initially the wall thickness of the sealing lip  341  decreases, but it increases again toward the edge  342 . 
       FIG.  7    shows the mask bead  3  in a front view, i.e., the side facing toward the user. The mask bead  3  is constructed mirror symmetrically and the mirror plane E 3  extends through the base region  32  and the nasal bridge region  33 , without extending through the side regions. On the outer side, thus the side facing toward the user, of the contact region  34 , the points p 1 , p 2  can be defined, as well as the mirror points p 1 ′ and p 2 ′ resulting therefrom. The points p 1  and p 1 ′ or p 2  and p 2 ′ are connected by connecting lines L 1 , L 2 . These connecting lines then span a plane E 1  in such a way that both connecting lines L 1 , L 2  and thus also the points p 1 , p 2  and their mirror points p 1 ′, p 2 ′ lie on the plane E 1 . Due to the mirror symmetrical structure of the mask bead  3 , the connecting lines L 1 , L 2  extend in parallel to one another. The planes E 1  and the mirror plane E 3  are perpendicular to one another. 
     The contact region  34  of the mask bead  3  is embodied, for example, as a sealing lip  341 . The sealing lip  341  extends here, for example, in such a way that the edge  342  of the sealing lip protrudes into the receptacle opening  30 . As can be seen in  FIG.  7   , the area of the receptacle opening  30  is defined by the edge  342  of the sealing lip. If the mask bead  3  is produced, for example, from an elastomeric or soft material, for example silicone, a change of the area of the receptacle opening  30  defined by the edge  342  can certainly result during the use of the breathing mask. The area of the receptacle opening  30  defined by the edge  342  can also vary during use depending on the facial contour of the user. 
     An exemplary embodiment of the mask bead  3  is outlined in  FIG.  8   , wherein the mask fitting  35  is not explicitly shown. The mirror plane E 3  intersects the nasal bridge region  33  and the base region  32  (concealed in  FIG.  8   ), without intersecting the side regions  31 . On the outer side of the contact region  34  facing toward the user, the points p 1 , p 2  are selected, as well as their mirror points p 1 ′, p 2 ′. The plane E 1  rests on these points and is furthermore defined by the connecting lines L 1 , L 2  extending in parallel between the points p 1  and p 1 ′ and p 2  and p 2 ′. The plane E 1  extends perpendicular to the mirror plane E 3 . 
       FIG.  9    shows a greatly simplified perspective illustration of an exemplary embodiment of the filter receptacle  41 . The filter receptacle  41  has significantly larger dimensions in the directions x 2  and y 2  than in the z 2  direction. A plane E 2  is spanned by the directions x 2  and y 2 , which extends essentially in parallel to the surface represented by the filter receptacle  41 . 
     In some exemplary embodiments of the breathing mask  1 , the plane E 2  extends essentially in parallel and at a distance to the plane E 1 . If the plane E 2  extends in parallel to the plane E 1 , the plane E 2  is thus also perpendicular to the mirror plane E 3 . The essentially parallel course of the planes E 1  and E 2  in relation to one another is to be understood in such a way that the plane E 2  can also extend inclined at a small angle in relation to one another. In some exemplary embodiments, for example, the plane E 2  extends at an angle between 0° and 15° in relation to the plane E 1  and perpendicular to the mirror plane E 3 . Furthermore, a course of the plane E 2  is also possible in which the plane E 2  is at an angle between 0° and 15° to both the plane E 1  and also the mirror plane E 3 . In some embodiments of the breathing mask  1 , the filter receptacle is arranged, for example, so that the contact surface  34  of the mask bead  3  delimits the respiratory gas chamber defined by the mask body  2 , the mask bead  3 , and the filter device  4  on the side facing toward the user and the filter receptacle  41  delimits it on the side facing away from the user. Such a structure of the breathing mask is also described for  FIGS.  1  and  3   . 
     In further exemplary embodiments, the plane E 2  extends perpendicularly to the plane E 1  and essentially in parallel to the mirror plane E 3 . For example, the plane E 2  can also be at an angle between 90° and 45° in relation to the plane E 1  and can possibly also be inclined at an arbitrary angle in relation to the mirror plane E 3 . For example, the planes E 1 , E 2  and the mirror plane E 3  are in relation to one another in such a way that the planes do not have any common point together. For example, the planes can also be in relation to one another in such a way that they only intersect in one point. 
     A perspective view of an exemplary embodiment of the filter holder  412  is shown in  FIG.  10   . A filter receptacle opening  416  is defined by the circular filter receptacle edge  415  of the filter holder  412 , through which filter receptacle opening  416  the respiratory gas can flow toward and away from the filter element  40 . In addition, the filter holder  412  has a positioning hole  4011 , which is closed on one side. The positioning hole  4011  is used for simplified positioning of the filter holder on the filter receptacle base  411 . Furthermore, for example, locking recesses  4022  are formed, using which the filter holder can be locked on the filter receptacle base on corresponding locking projections  4021 . A fixed connection between filter receptacle base  411  and filter holder  412  is ensured, for example, by the locking. The filter element  40  is thus also fastened in the filter receptacle  41 , thus clamped in, for example, and secured from falling out. If the filter element  40  consists exclusively of the filter material  401 , for example, the filter material  401  is pinched or clamped by the locking of the filter holder  412  on the filter receptacle base  411  in such a way that respiratory gas can flow exclusively through the filter material  401 . For further securing against the filter element  40  falling out, two webs  414  are additionally arranged on the filter holder  412 . For example, these webs  414  are arranged so that they meet or intersect in the center in the filter receptacle opening  416  defined by the filter receptacle edge  415  of the filter holder  412 . The webs  414  can moreover also be embodied in any arbitrary other number or in other profiles or can be completely absent. In further exemplary embodiments, for example, three webs  414  extend in parallel to one another. The shape of the filter holder  412 , which is primarily defined by the shape of the filter receptacle edge  415 , for example, can also vary. Thus, for example, in addition to a circular embodiment, a square or rectangular shape of the filter holder  412  is also possible. In addition, other polygons, oval shapes, and free forms are possible as the geometry of the filter holder  412 . 
       FIG.  11    shows an exemplary embodiment of a filter element  40  for the breathing mask  1  according to the invention, wherein the filter element  40  only consists of filter material  401 . The filter material  401  has a positioning hole  4011  for easier positioning on the filter receptacle lug  413  of the filter receptacle base  411 . The material of the filter material  401  is to be selected in such a way that germs (e.g., viruses, bacteria, fungi) and/or other microorganisms can be filtered out of the respiratory gas or the respiratory air by the filter material  401  and retained. The filter element  40  shown by way of example can also equipped with one or more filter frames  42  in addition to the filter material  401 . Easier insertion and removal of the filter element  40  into or from, respectively, the filter receptacle  41  is simplified by the embodiment having at least one filter frame  42 , for example, and a filter holder  412  can be saved depending on the embodiment. For this purpose, for example, the filter frame  42  can also take over functions of the filter holder  412 , for example, the locking on or in the filter receptacle base  411 . For this purpose, for example, the required locking devices  402  would be attached to the filter frame  42  instead of to the filter holder  412 . If the filter receptacle base  411  does not have, for example, a filter receptacle lug  413 , a positioning hole for the filter element  40  is thus also not provided, so that no opening results through which respiratory gas can flow without passing the filter material  401 . For example, the filter material  401  consists of polypropylene. For example, however, other materials are also conceivable for use as the filter material  401 , for example, other plastic fibers arranged in a finely woven manner. 
     In a further embodiment, the filter material  401  consists, for example, of a gas-permeable container or bag which is filled with a filter material, for example activated carbon. 
     A further exemplary embodiment of a filter element  40  is shown in a schematic front view in  FIG.  12   a    and the schematic cross section in side view  12   b . The filter element  40  has an essentially cuboid shape and consists, for example, of two filter frames  42  between which a filter material  401  is arranged. The filter material  401  is, for example, clamped between the two filter frames  42 , wherein the two filter frames  42  are clamped with one another by corresponding locking devices  402 . The filter material  401  is corrugated or folded like an accordion in the embodiment shown, by which the filter surface area is increased without enlarging the area of the filter element  40 . However, a completely flat embodiment of the filter material  401  is also possible in the arrangement shown in  FIG.  12   a   . The filter frames  42  have webs  414  in each case, which are used, inter alia, to hold the filter material  401  between the filter frames  42  and secure it against slipping out. In addition, a certain additional stability is provided to the filter frame  42  by the webs  414 . For the exemplary fastening of the filter element  40  in a filter receptacle  41 , a locking device  402  and a handle  404  are attached to the filter element  40 , more precisely to one of the filter frames  42 . The locking device  402  is embodied so that the counterpart is attached to the filter receptacle  41  (not shown in greater detail), so that the filter element  40  can be locked accordingly via the locking device  402  and is thus solidly seated in the filter frame  41  and secured against falling out. For easy handling, for example, a handle  404  is attached to the filter frame  42  which does not have to coincide with the locking device  402 . In the exemplary embodiment shown, the handle  404  is attached together with the locking device  402  on the filter frame  42 . This handle  404  can enable, for example, easy changing of the filter element  40 . For example, the user can release the filter element  40  from the filter receptacle  41  via grasping the handle  404  and insert a new filter element  40  and lock it in the filter receptacle  41  via the locking device  402  during the use of the breathing mask  1 , without removing it. The greatly simplified outline of the cross section of the filter element  40  shown by way of example in  FIG.  12   b    additionally illustrates the location of the filter material  401  relative to the filter frames  42 . The exemplary filter element  40  is conceived so that the side having the handle  404  and the locking device  402  is located on the outer side of the breathing mask  1 . 
     The pinching or clamping of the filter material  401  in the filter frames  42 , which are connected to one another via locking devices  402 , enables, for example, changing of the filter material  401 . The two filter frames  42  can also be permanently connected to one another, for example, by adhesive bonding, for example. The filter material  401  can also be permanently connected to the filter frames  42  in this case—also by adhesive bonding, for example—or simply laid between the filter frames  42  and clamped. 
     Alternatively or also additionally to the locking device  402 , for example, guide rails can also be attached to the filter element  40 . Together with corresponding guide rails on the filter receptacle  41 , an easy change of the filter element  40  can thus also be achieved. 
     A further exemplary embodiment of the filter receptacle base  411  and of the filter holder  412  is schematically outlined in  FIGS.  13   a    (top view or bottom view) and  13   b  (side views). The filter receptacle base  411 , which is shown by way of example in a top view in  FIG.  13   a   , has a filter receptacle lug  413 , which enables easy positioning of the filter element  40  and the filter holder  412 . The filter receptacle lug  413  is attached for this purpose, for example, on the intersecting webs  414 , wherein the webs can also be positioned differently. For the connection of the filter receptacle base  411  to the filter holder  412  shown by way of example in a bottom view in  FIG.  13   a   , screw threads  403  are arranged on both components. The screw threads  403  are embodied in such a way that they interlock and the filter holder  412  can be screwed solidly into the filter receptacle base  411 . The filter element  40 , for example, consisting only of the filter material  401 , can be laid on the webs  414  and the filter receptacle edge  415  and then solidly pinched or clamped in the filter receptacle base  411  by screwing in the filter holder  412 . For easy screwing of the filter holder  412  into the filter receptacle base  411 , the filter holder  412  has, for example, a handle  404 , as schematically shown in  FIG.  13   b   . The filter holder  412  has, for example, a positioning hole  4011 , which is embodied matching with the filter receptacle lug  413 , so that easy positioning of the filter holder  412  is enabled. In the illustrated exemplary embodiments of the filter receptacle base  411  and filter holder  412 , the screw threads are applied in such a way that they are internal in the filter receptacle base  411  (indicated by the dashed line in  FIG.  13   b   ) and are external in the filter holder  412 . The screw threads can also be arranged the opposite way, for example, thus on the outside of the filter receptacle base  411  and on the inside of the filter holder  412 . 
     In a further embodiment, for example, the component designated in  FIGS.  13   a, b    as the filter holder  412  is also used as the filter frame  42  for the filter element  40 . For this purpose, for example, the filter material  401  is connected to the corresponding component—for example by adhesive bonding. A simple possibility can thus also be provided, for example, to change the filter element  40  during the wearing, thus the use, of the breathing mask  1 , for example, also without touching the other components of the breathing mask  1 . In further embodiments, constructing the filter element from two or more filter frames  42  is also conceivable. The filter frames  42  can thus also be constructed in accordance with the filter holder  412  and filter receptacle base  411  shown in  FIGS.  13   a, b   , between which the filter material  401  is arranged. The filter element  40  thus constructed can then be pressed, for example, into a filter receptacle  41  embodied as a simple opening and made of a soft or elastomeric plastic. Alternatively, arranging a further screw thread  403  on the filter element  40  and in the filter receptacle  41  would also be conceivable, so that the filter element  40  can be screwed into the filter receptacle. 
     In addition to the possibilities described on the basis of the Figures for inserting the filter element  40  into the filter receptacle  41  and locking it, all further possibilities for inserting the filter element replaceably in the filter receptacle  41  also correspond to the breathing mask  1  according to the invention. For this purpose, for example, a connection of the filter receptacle base  411  and the filter holder  412  via a type of hinge would also be possible, opposite to which a locking device  402  is located. To change the filter element  40 , the filter receptacle  41  can be folded open so that the filter element  40  can be removed and exchanged. After exchanging the filter element  40 , the filter receptacle  41  can be folded closed again and locked in such a way that the filter element  40  is solidly seated in the receptacle. 
     In some exemplary embodiments, the filter receptacle  41  and the filter element  40  are adapted and configured to one another in such a way that it is possible to replace the filter element  40  with few actions. This includes, for example, changing the filter element  40  while wearing the breathing mask  1  without having to touch components of the breathing mask  1  other than the filter element itself. For this purpose, for example, an embodiment of the filter element  40  having a filter frame  42  which has a screw thread  403  is suitable, wherein the filter receptacle  41  also has a corresponding screw thread  403 . A further easy replacement option can be represented, for example, by a filter element  40  which does not have locking devices  402  or the like and is pressed, for example, into a filter receptacle  41  produced from a soft plastic and thus can also be pulled out. The breathing mask  1  still presses in a respiratory-gas-tight manner against the face of the user here, for example, due to the head fastening strap  52  and the strap holder  5 . 
     A further exemplary embodiment of the breathing mask  1 , consisting of a filter holder  412 , a filter material  401 , a filter receptacle base  411 , and the mask body  2 , which is embodied integrally with the mask bead  3 , is shown in  FIGS.  14  to  20   . 
       FIG.  14   a    shows by way of example a filter holder  412  in the rear view, thus the side which faces in the direction of the user during use of the mask. The filter holder edge  419  is made essentially triangular, wherein the corners are rounded. Tabs  4023  are arranged on the sides of the filter holder edge  419 , which, together with the filter holder edge  419 , form the locking recesses  4022 . The tabs  4023  are aligned so that they point roughly in the direction of the user, as can be seen in the perspective view in  FIGS.  14   c  and  14   d   . The tabs  4023  in conjunction with the locking recesses  4022  are used for locking the filter holder  412  on the filter receptacle base  411 . In combination with locking projections  4021  of the filter receptacle base  411 , the filter holder  412  can thus be locked, for example, via a clip or click mechanism on the breathing mask  1 . 
     A mounting projection  418  is arranged on top—approximately corresponding to the tip of the triangle—on the filter holder edge  419 . This mounting projection  418  is designed, for example, so that it can only be assembled in one position and direction with the remaining components of the breathing mask  1 . For example, a corresponding groove  21  is formed for this purpose in the mask body  2 , into which the mounting projection  418  can be inserted. In some embodiments, the mounting projection  418  and the groove  21  are designed so that the mounting projection  418  can lock in the groove  21  via a clip or click mechanism. 
     Starting from the filter holder edge  419  in the direction of the center  422  and around the center  422 , filter holder webs  426  extend, which form the filter holder openings  427  due to the spacing in relation to one another. The respiratory gas can flow through the filter holder openings  427  during use of the breathing mask  1 . For example, starting from the corners of the filter holder edge  419 , three filter holder webs  426  extend to the center  422 . These three filter holder webs  426  are connected to one another by a triangular arrangement of further filter holder webs  426 . Moreover, for example, starting from two sides of the filter holder edge  419 , two further filter holder webs  426  extend in the direction of the center  422 , wherein these merge into the triangular arrangement of the webs. 
     A pressing edge  423  is formed on the filter holder edge  419  and on the filter holder webs  426 . With respect to the filter holder edge  419  in the perspective shown in  FIG.  14   a   , for example, the pressing edge  423  extends without interruption on the inner side (closer to the center  422 ) of the filter holder edge  419 , so that respiratory gas can only flow through the filter material  401  in the completely assembled breathing mask  1 . For this purpose, the pressing edge  423  is designed so that it presses on or partially into the filter material  401 . The pressing edge  423  is thus also used, for example, for additional fixing of the filter material  401  between filter holder  412  and filter receptacle  413 . The filter holder  412  is slightly bulging, for example, wherein the pressing edge  423  establishes a plane and the filter holder webs  426  and the filter holder edge  419  form a bulge in the lower region, thus opposite the mounting projection  418 . The height of the pressing edge  423 , which starts from the filter holder edge  419  and the filter holder webs  423 , thus varies. 
       FIG.  14   b    shows the exemplary filter holder  412  from  FIG.  14   a    in a front view. As in  FIG.  14   a   , it can also be seen in the front view of  FIG.  14   b    that the filter holder frame is formed essentially triangularly having rounded corners. Starting from the filter holder edge  419 , the filter holder webs  426 , which also form the filter holder openings  427  by the spacing in relation to one another and to the filter holder edge  419 , extend toward the center  422 . Moreover, the tabs  4023  which are used for locking the filter holder  412  on the filter receptacle base  411  are arranged to the sides of the filter holder edge  419 . 
     In some embodiments, the filter holder  412  is produced from a dimensionally stable plastic. A production from deformable or elastomeric plastics, such as silicones, is also conceivable. The filter holder  412  is preferably produced integrally, for example, by injection molding. 
     An exemplary embodiment of the filter receptacle base  411  is schematically shown in  FIGS.  15   a - d    and  16   a, b  in various perspectives and details. Together with the filter holder  412 , the filter receptacle base forms the filter frame  42 , which can accommodate the filter material  401 . 
     Matching with the shape of the filter holder  412  or the pressing edge  423 , the filter receptacle base  411  is made trapezoidal, as the front view (faces away from the user) in  FIG.  15   a    shows. The filter receptacle edge  425  essentially encloses the filter receptacle opening  416  here. Moreover, the filter receptacle webs  414  extend from the filter receptacle edge  425  into the filter receptacle opening  416  and accordingly divide it into multiple smaller openings. On the filter receptacle webs  414  are arranged holding tips  417 , which are formed so that they press onto and/or into the filter material  401  without piercing it. An enlarged schematic view of the holding tips  417  is shown in  FIG.  15   d   , wherein the detail corresponds to detail D 1  from  FIG.  15   c   . The holding tips  417  are, for example, conical protrusions on the filter receptacle webs  414 , wherein the tip is flattened. In addition, the holding tips  417  can also have various other shapes, inter alia, also because of the production of the filter receptacle base  411 , for example, by injection molding. For example, fixing of the filter material  401  in the filter receptacle base  411  or the filter frame  42  is achieved by the holding tips. A pressing edge  424 , which is slightly elevated in relation to the filter receptacle edge  425 , extends along the filter receptacle edge  425  in the region of the filter receptacle opening  416 . For example, the pressing edge  424  has a height of 0.1 mm to 2.0 mm, preferably between 0.3 mm and 0.8 mm. The pressing edge  424  is pressed onto the filter material  401  during the assembly of the breathing mask  1 , so that respiratory gas only flows through the filter material  401  through the filter receptacle opening  416  and to the user through the filter holder openings  427 . To achieve a taller overlap region between pressing edge  424  and the filter material  401 , the pressing edge  424  is made crowned, for example, thus bulging somewhat into the filter receptacle opening  416 . For example, the filter receptacle webs  414  of the filter receptacle base  411  do not have a pressing edge, like, for example, the exemplary embodiment of the filter holder webs  426  according to  FIG.  14   a   . Additionally or alternatively to the exemplary holding tips  417 , however, additional pressing edges can also be formed on the filter receptacle webs  414 . 
     Locking projections  4021  are arranged on the outer sides of the filter receptacle edge  425  of the filter receptacle base  411 . These locking projections  4021  are guided during the assembly of the breathing mask  1 , for example, through the mounting openings  4024  of the mask body  2  and are used together with the tab  4023  and the locking recesses  4022  for locking the filter holder  412  on the filter receptacle base  411 . As can be seen in the perspective view of the filter receptacle base  411  in  FIG.  15   b   , the locking projections  4021  are angled slightly in the direction of the rear side, thus in the direction of the user. If, for example, a tab  4023  is guided over the locking projections  4021 , the tab  4023  thus hooks under the locking projections  4021 . The filter holder  412  can thus be locked securely on the filter receptacle base  411 . 
     For simplified mounting and to avoid assembling the breathing mask  1  incorrectly, a mounting projection  420  is arranged on the filter receptacle edge  425 . When the breathing mask  1  is assembled, the mounting projection  420  extends below the lower edge of the filter material  401  and the pressing edge  423  of the filter holder  412 . With respect to the mask body  2 , a recess  22  is formed there which can accommodate the mounting projection  420 . For example, the mounting projection  420  can also be used to align the filter material  401  in that the lower edge of the filter material  401  is placed on the mounting projection  420  before the filter holder  412  is pressed onto the filter receptacle base  411  and locked. A matching alignment of the components in relation to one another is moreover promoted by the essentially triangular or trapezoidal formation of the filter holder  412 , the filter receptacle base  411 , and the filter material  401 . 
     Starting from the filter receptacle edge  425 , as can be seen in  FIG.  15   b   , a mounting edge  428  extends on the rear side (direction of the user) of the filter receptacle base  411 , on which edge two mounting ribs  421  are in turn formed. The mounting edge  428  having the mounting ribs  421  is inserted into the central opening of the mask body  2  for assembly of the breathing mask  1  and is used, for example, for simplified and correctly oriented insertion into the mask body  2 . In addition, the filter receptacle base  411  is held in the mask body  2  by the locking projections  4021 , which are inserted through the mounting openings  4024  of the mask body  2 . 
       FIGS.  16   a  and  16   b    show an exemplary embodiment of the filter receptacle base  411  in a side view. Starting from the filter base edge  425 , the pressing edge  424  and the mounting projection  420  are raised on one side. On the other side of the filter receptacle base  411 , the mounting edge  428  extends starting from the filter base edge  425 . 
     Details of the mask bead  3  of the exemplary embodiment of the breathing mask  1  are shown in  FIGS.  17   a  and  17   b   .  FIG.  17   a    shows the nasal bridge region  33  of the mask bead  3 . It can be seen that the material thickness is substantially constant from the transition  344  up to the edge  342  of the sealing lip. For example, the material thickness of the mask bead  3  in the region of the nasal bridge region  33  is between 0.1 mm and 0.8 mm, preferably between 0.3 mm and 0.5 mm. To ensure a stable seat of the breathing mask  1 , the material thickness in the base region  32  of the mask bead  3  coming from the transition  344  is initially greater and decreases in the direction of the edge  342  of the mask bead  3 . In the region of the transition  344 , the material thickness is, for example, between 0.5 mm and 2.0 mm, preferably between 0.7 mm and 1.5 mm. Toward the edge  342 , the material thickness is reduced to between 0.1 mm and 0.8 mm. Similar profiles of the material thicknesses can also be formed, for example, in the side regions  31  of the mask bead  3 . Overall, the material thickness of the mask bead  3  is dependent on the region of the mask bead  3  and also on which point of the facial skin of the user the respective region rests. The material thickness is thus to be selected as less in the region of more sensitive points of the facial skin, while at other points a greater material thickness can be selected to stabilize the mask bead  3 . 
     The mask body  2  is, for example, produced integrally with the mask bead  3 , as shown in  FIGS.  18   a - c   . For example, the mask body  2  is manufactured in one piece with the mask body  3  and from one material. A silicone, for example, a liquid silicone rubber, is preferably used for this purpose. The Shore hardness of the material used is, for example, between 40 and 80 Shore A, wherein a maximum elasticity between 50% and 600% can be achieved. In particular for the mask body  2 , other materials are also usable, for example, elastic or elastomeric plastics or dimensionally stable plastics such as polycarbonate, polystyrene, polyamide, etc. In the mask body  2  and the mask bead  3 , it is to be ensured here that they are not permeable to respiratory gas—with the exception of the opening  24 ,  30  provided for this purpose. Starting from the transition  344  from the mask body  2  to the mask bead  3 , for example, the material thickness increases, so that the mask body  2  largely has a greater material thickness than the mask bead  3 . It is also to be noted here that the transition  344  can also be made continuous, so that no clear boundary is recognizable between mask body  2  and mask bead  3 . The material thickness of the mask body  2  is, for example, between 1.5 mm and 5 mm, preferably between 1.5 mm and 3 mm. In some regions, in particular in the region of the opening  24  of the mask body  2 , the resulting material thickness can be less at points, for example to enable mounting of components such as the filter receptacle base  411  or the filter holder  412 . 
     The ratio of the distance between the corner points  311  and  314  to the distance between the corner points  312  and  313  is between 1:2 and 1:8. 
     In the exemplary embodiment shown of the mask body  2  having the mask bead  3 , the strap holders  5  are also integrally connected to the mask body  2 . For example, the strap holder  5  consists of a fastening projection  50  on the outer side of the mask body  2 , wherein the fastening projection  50  in turn has two feedthrough openings  51 . The number of feedthrough openings  51  and/or fastening projections  50  can vary here and can be adapted in accordance with the intended number of fastening straps  52 . The feedthrough openings  51  are configured, for example, so that a head fastening strap  52  can be guided through the feedthrough openings  51 . For example, protrusions  521  are formed on the head fastening strap  52 , which are used for fixing the head fastening strap  52  in the strap holder  5 . For this purpose, the fastening projection  50  is made of an elastic material, for example, so that the feedthrough openings  51  can be made smaller in height and width than the protrusions  521 . Due to the elasticity of the fastening projection  50 , the protrusions  521  can be guided through the feedthrough openings  51  with application of force. To guide the protrusions  521  in the opposite direction through the feedthrough openings  51  again, a certain application of force is also necessary, so that a corresponding fixation of the head fastening strap  52  in the strap holder results. 
     Mounting openings  4024  are formed in the side walls  25  of the mask body  2  in the region of the opening  24 , which is used for mounting the filter frame  42 , consisting of filter holder  412 , filter receptacle base  411 , and filter material  401 . The locking projections  4021  of the filter receptacle base  411  are guided through these mounting openings  4024 , so that they can be fixed/locked in the mask body  2 . In the exemplary embodiment from  FIGS.  18   a - c   , a mounting edge  23  is formed in the region of the opening  24  which is adapted to the dimensions of the mounting edge  428  of the filter receptacle base  411 , for example, to assist correct mounting of the filter receptacle base  411  in the mask body  2 . The mounting edge  23  protrudes here from the edge  26  into the opening  24 . For example, the dimensions of the mounting edge  23  are slightly smaller, so that the filter receptacle base  411  can be pressed into the opening  24  on the inner side of the mounting edge  23  and held there. The slightly smaller dimensions of the mounting edge  23  are also used, for example, for the respiratory-gas-tight enclosure of the filter receptacle base  411 . The recess  22  in the region of the opening  24  is formed so that the recess  22  can accommodate the mounting projection  420  of the filter receptacle base  411 . Moreover, a groove  21 , which can accommodate the mounting projection  418  of the filter holder  412 , is formed in the region of the opening  24  for correct positioning of the filter holder  412 . The edge  26  is formed toward the opening  24  so that the filter holder  412  can be inserted in a precisely fitted manner and enclosed in a respiratory-gas-tight manner, so that respiratory gas on the side of the opening  24  can only flow through the filter holder openings  427 , the filter receptacle openings  416 , and the filter material  401  into the interior of the breathing mask  1 . 
     The exemplary embodiment of the mask bead  3 , which is integrally connected to the mask body  2 , largely corresponds to the exemplary embodiment of the mask bead  3  described in  FIG.  5   . While the material thicknesses of the mask bead  3  are designed, for example, for wearing comfort, sealing, and wearing stability, the material thicknesses in the region of the mask body  2  are comparatively greater to ensure general mechanical stability of the mask body  2  and to counteract undesired deformations, which could result in leaks. 
     An exemplary embodiment of the assembled breathing mask  1  is shown in  FIGS.  19   a  and  19   b   . The mask bead  3  merges into the mask body  2 . The filter receptacle base  411  is inserted into the mask body  2 , of which filter receptacle base  411  only the locking projections  4021  are visible in the perspective shown. The filter material  401 , which is fixed by the filter holder  412 , is laid on the filter receptacle base  411 . The filter holder  412  is fixed with the aid of the tab(s)  4023  via the locking projections  4021  on the filter receptacle base  411  and on the mask body  2 . Respiratory gas can only flow from the side of the mask body  2  through the filter material  401  and the filter holder openings  427  into the interior of the breathing mask  1  when the breathing mask  1  presses in a respiratory-gas-tight manner with the mask bead  3  on the facial skin of the user. In  FIG.  19   b    it is shown by way of example in detail how the tab  4023  is clamped behind the locking projections  4021  and thus locks the filter holder  412 . 
     The breathing mask  1  in the assembled state, without straps, has a maximum width (cf. B in  FIG.  18   b   ) at the widest point between 75 mm and 105 mm. The maximum height (cf. H in  FIG.  18   c   ) of the breathing mask  1  is between 80 mm and 130 mm, wherein the maximum depth of the breathing mask  1  is between 50 mm and 90 mm. 
     In addition, the structure of the breathing mask  1  is clarified by the exploded view of the breathing mask  1  in  FIG.  20   . The filter receptacle base  411  is inserted into the mask body  2 . The filter material  401 , which is fixed between the filter receptacle base  411  and the filter holder  412  by the pressing edges  423 ,  424  and the holding tips  417 , is arranged on the filter receptacle base  411 . The filter holder  412  is locked with the aid of the tab  4023  on the locking projections  4021 , which are guided through the mounting openings  4024 . For simplified alignment, on the one hand, it is provided that the mounting projection  420  is accommodated by the recess  22  and, on the other hand, it is provided that the mounting projection  418  is inserted into the groove  21  of the mask body  2 . 
     For example, the mask body  2  is made of an elastic material, for example, an elastomeric plastic such as silicone, and in dimensions such that the filter receptacle base  411  and the filter holder  412  have to be pressed at least partially into the mask body  2 , that is to say the mask body is somewhat smaller. A respiratory-gas-tight fixation of the filter receptacle base  411  and the filter holder  412  can thus be ensured, for example. 
     The head fastening strap  52 , which is guided through the feedthrough openings  52  of the strap holder  5 , has protrusions  521  in some embodiments, which are used for fixing—inter alia therefore for the prevention of an adjustment. Furthermore, openings  522  are formed at the ends of the head fastening strap  51  which can accommodate the holding clip  54 . The holding clip  54  has for this purpose a holding shaft  542  which is formed on a clip body  543  and can be accommodated by the opening  522 . To prevent the holding shaft  542  from slipping out, a holding safeguard  541  is formed on the holding shaft  542 , which is significantly larger in circumference than the opening  522 . The head fastening strap  52  is preferably manufactured from an elastic material, so that the opening  522  for mounting the holding clip  54  on the head fastening strap  52  can at least temporarily be expanded enough that the holding safeguard  541  can be guided through the opening. The clip body  543  is made C-shaped, for example, and can be slipped over the head fastening strap  52 , for example, between two protrusions  521 . The holding clip  54  thus fulfills at least two tasks, on the one hand, the holding clip helps in the fixing of the head fastening strap  52  and secures against inadvertent widening of the straps, which can result in a looser seat of the breathing mask  1 . On the other hand, the loose end of the head fastening strap  52  can be fixed by the holding clip  54  to avoid annoying movements of the end of the head fastening strap  52 . For example, the holding clip  54  is made of a dimensionally stable plastic, but other materials, for example, elastic materials, are also conceivable for the holding clip. 
     LIST OF REFERENCE SIGNS 
     
         
           1  breathing mask 
           2  mask body 
           3  mask bead 
           4  filter device 
           5  strap holder 
           21  groove 
           22  recess 
           23  mounting edge 
           24  opening 
           25  side wall 
           26  edge 
           30  receptacle opening 
           31  side region 
           32  base region 
           33  nasal bridge region 
           34  contact region 
           35  mask fitting 
           40  filter element 
           41  filter receptacle 
           42  filter frame 
           50  fastening projection 
           51  feedthrough opening 
           52  head fastening strap 
           53  loop 
           54  holding clip 
           311  corner point 
           312  corner point 
           313  corner point 
           314  corner point 
           341  sealing lip 
           342  edge of the sealing lip 
           343  notch 
           344  transition 
           401  filter material 
           402  locking device 
           403  screw thread 
           404  handle 
           411  filter receptacle base 
           412  filter holder 
           413  filter receptacle lug 
           414  filter receptacle web 
           415  filter receptacle edge 
           416  filter receptacle opening 
           417  holder tip 
           418  mounting projection 
           419  filter holder edge 
           420  mounting projection 
           421  spacer rib 
           422  center 
           423  pressing edge 
           424  pressing edge 
           425  filter base edge 
           426  filter holder web 
           427  filter holder opening 
           428  mounting edge 
           521  protrusion 
           522  opening 
           541  holding safeguard 
           542  holding shaft 
           543  clip body 
           4011  positioning hole 
           4021  locking projection 
           4022  locking recess 
           4023  tab 
           4024  mounting opening 
         A direction toward the user 
         D 1  detail 
         D 2  detail 
         E 1  plane 
         E 2  plane 
         E 3  mirror plane 
         L 1  connecting line 
         L 2  connecting line 
         p 1  point on contact region 
         p 1 ′ point on contact region 
         p 2  mirror point on contact region 
         p 2 ′ mirror point on contact region