CN111713777A

CN111713777A - Gauze mask

Info

Publication number: CN111713777A
Application number: CN202010568769.9A
Authority: CN
Inventors: 赵毅武; 范冬梅; 张良; 刘云; 余宗炜; 卢彦成; 董骧
Original assignee: Nantong Medical Protective Equipment Tianjin Co ltd; Beijing Naton Medical Technology Institute Co ltd
Current assignee: Nantong Medical Protective Equipment Tianjin Co ltd; Beijing Naton Technology Group Co Ltd
Priority date: 2020-06-19
Filing date: 2020-06-19
Publication date: 2020-09-29
Anticipated expiration: 2040-06-19
Also published as: CN111713777B

Abstract

The invention discloses a mask, which comprises a mask body and a first folding piece, wherein the first folding piece is arranged on the inner side surface of the mask body and can be folded between a closed position and an open position, the first folding piece is provided with a first side surface, the first side surface is a curved surface and is provided with a first convex part, a second convex part and a concave part positioned between the first convex part and the second convex part, the concave part is generally in an arc shape recessed towards the second side surface, the distance between the highest point of the first convex part and the highest point of the second convex part is 25.1887mm-68.734mm, and the shortest distance between the lowest point of the concave part and the highest point of the first convex part or the highest point of the second convex part in the width direction of the first folding piece is 2.4631mm-6.7213 mm. The mask disclosed by the invention can be better matched with the nose shape of a human body, the fit degree of the mask and the nose bridge is ensured, and the sealing property and the protection property of the mask are enhanced.

Description

Gauze mask

Technical Field

The invention relates to the technical field of medical treatment and health, in particular to a mask.

Background

The mask is a sanitary protection tool, is used for reducing or preventing harmful particles in the air, including germs, viruses, suspended particles, harmful gases and the like from being inhaled into the lungs, ensures that a wearer inhales pure air to a certain extent, and is widely applied to the fields of labor protection and health care. Particularly in some environments with high pollution levels, wearing an effective protective mask has become a necessary protective tool.

In order to ensure that the mask has a good protection effect, the mask and the face are required to be well attached, otherwise, harmful gas easily enters the internal breathing space from the gap between the mask and the face, and is particularly easy to inhale from two sides of the bridge of the nose. In the related art, a concave part is arranged at the position of the mask corresponding to the nose bridge or a batten is additionally arranged, but the mask is poor in fitting degree with the nose bridge in the form of arranging the concave part; to the form that sets up the layering, the layering appears becoming flexible the deformation easily when the user exhales, and the protectiveness of above-mentioned two kinds of structures can't obtain guaranteeing promptly.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the mask provided by the invention has the advantages of high fit degree with the position of the nose bridge and good sealing and protecting effects.

The mask according to the embodiment of the present invention includes a mask body; a first flap provided on an inner side surface of the cover body and foldable between a closed position and an open position, the first flap including a first side surface and a second side surface arranged opposite to each other in a width direction thereof, the first flap being attached to the inner side surface of the cover body in the closed position, at least a part of the first flap being away from the inner side surface of the cover body in the open position so that the first side surface of the first flap faces inward, the first side surface of the cover body being a curved surface and having a first convex portion, a second convex portion, and a concave portion located between the first convex portion and the second convex portion, the concave portion being substantially an arc shape recessed toward the second side surface, a distance between a highest point of the first convex portion and a highest point of the second convex portion being 25.1887mm to 68.734mm, and a shortest distance between a lowest point of the concave portion and a highest point of the first convex portion or a highest point of the second convex portion in the width direction of the first flap Is 2.4631mm-6.7213 mm.

According to the mask provided by the embodiment of the invention, the size range which is most suitable for the nose shape of the Chinese is obtained by measuring, investigating and calculating a large number of face shapes and nose shapes of the Chinese, so that the mask provided by the embodiment of the invention can be better attached to the nose bridge of the Chinese, and the sealing property and the protection property of the mask are enhanced.

In some embodiments, the distance between the highest point of the first convex portion and the highest point of the second convex portion is 40.1887mm-60.734mm, and the shortest distance from the lowest point of the concave portion to the highest point of the first convex portion or the highest point of the second convex portion in the width direction of the first flap is 4.4631mm-5.6213 mm.

In some embodiments, the distance between the highest point of the first convex portion and the highest point of the second convex portion is 54.2mm, and the shortest distance from the lowest point of the concave portion to the highest point of the first convex portion or the highest point of the second convex portion in the width direction of the first flap is 5.3 mm.

In some embodiments, the first convex portion and the second convex portion are both arc segments, and the radius of the arc segments is 15 mm.

In some embodiments, the concave portion includes a first arc segment, a second arc segment, and a third arc segment that are connected in sequence, and the first arc segment and the third arc segment both protrude in a direction toward the second side surface, and the second arc segment protrudes in a direction away from the second side surface.

In some embodiments, the first convex portion, the first arc segment, the second arc segment, the third arc segment, and the second convex portion are sequentially tangent.

In some embodiments, the radius of the first and third arc segments are both 46.34mm, and the arc length of the first and third arc segments are both 20.27 mm; the radius of second circular arc section is 50mm, the arc length of second circular arc section is 2.69 mm.

In some embodiments, the concave portion is a circular arc segment with a radius of 60.19mm, and two ends of the concave portion are tangent to the first convex portion and the second convex portion respectively.

In some embodiments, the first side of the first flap further comprises a first diagonal segment and a second diagonal segment, wherein one end of the first diagonal segment is tangent to the first protrusion, the other end of the first diagonal segment is connected to the cover via a first bend, one end of the second diagonal segment is tangent to the second protrusion, and the other end of the second diagonal segment is connected to the cover via a second bend.

In some embodiments, the first and second diagonal segments are inclined at an angle of 15 °.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

Fig. 1 is a schematic view of the structure of a mask according to an embodiment of the present invention;

FIG. 2 is a schematic view of a first flap of a mask according to an embodiment of the present invention in a closed position;

fig. 3 is an exemplary schematic view of a first flap of a mask according to an embodiment of the present disclosure;

fig. 4 is a schematic view showing a mask body structure of a mask according to an embodiment of the present invention;

fig. 5 is another exemplary schematic view of a first flap of a mask according to an embodiment of the present disclosure;

fig. 6 is yet another exemplary illustration of a first flap of a mask according to an embodiment of the present disclosure;

fig. 7 is a schematic view of a second flap of a mask according to an embodiment of the present invention in a closed position;

fig. 8 is a schematic view of a first flap of a mask according to an embodiment of the present invention showing a slot width L and a slot depth H;

fig. 9 is a schematic view of a first flap of a mask according to an embodiment of the present invention showing the arc length of a plurality of circular segments.

Reference numerals:

the cover body 1 is provided with a plurality of grooves,

a first flap 2, a first side surface 21, a first protrusion 211, a second protrusion 212, a recess 213, a first arc segment 2131, a second arc segment 2132, a third arc segment 2133, a first diagonal segment 214, a second diagonal segment 215, a first bend 216, a second bend 217, a second side surface 22, a first body portion 23, a first folded portion 24,

a second flap 3, a second body 31, and a second folded portion 32.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

As shown in fig. 1 and 2, a mask according to an embodiment of the present invention includes a mask body 1 and a first flap 2. The mask body 1 is the main body of the mask and plays a role in filtering air.

The first flap 2 includes a first side 21 (e.g., the lower side of the first flap 2 in fig. 1 and 2) and a second side 22 (e.g., the upper side of the first flap 2 in fig. 1 and 2) which are arranged opposite to each other in the width direction (e.g., the up-down direction in fig. 1), and the first flap 2 is provided on the inner side of the cover 1 and can be folded between the closed position and the open position. The inner side surface of the cover 1 is a surface that comes into contact with a human face.

In the closed position, the first flap 2 abuts the inner side of the cover 1, and in the open position, at least part of the first flap 2 is away from the inner side of the cover 1 so that the first side 21 of the first flap 2 faces inward. As shown in fig. 1, when the user uses the mask, at least a portion of the first flap 2 may be folded inwards and upwards to make the first flap 2 located at the open position, so that the lower side of the first flap 2 faces the face of the user and is convenient to fit with the bridge of the nose, thereby playing a role in protection and sealing.

The first side surface 21 of the cover 1 is a curved surface and has a first convex portion 211, a second convex portion 212, and a concave portion 213 located between the first convex portion 211 and the second convex portion 212, and the concave portion 213 is substantially in the shape of an arc concave toward the second side surface 22. The first side surface 21 is a curved surface and can better fit with the face, and the first side surface 21 is provided with a first convex part 211, a second convex part 212 and a concave part 213, and the concave part 213 is arranged between the first convex part 211 and the second convex part 212 and is in a generally arc shape concave towards the second side surface 22, so that the first side surface 21 can better fit with the bridge of the nose.

The distance (L shown in fig. 8) between the highest point of the first convex portion 211 and the highest point of the second convex portion 212 is 25.1887mm to 68.734mm, and the shortest distance (H shown in fig. 8) from the lowest point of the concave portion 213 to the highest point of the first convex portion 211 or the highest point of the second convex portion 212 in the width direction (up-down direction shown in fig. 2) of the first flap 2 is 2.4631mm to 6.7213 mm.

The inventor finds that the mask in the related art is universal for eastern and western people, however, noses of the eastern people and the western people are different, the eastern people use the mask in the related art, the fitting degree of the nose bridge position and the mask is not strong, and the sealing performance is not good. Therefore, the inventor designs the mask of the application by researching the nose shape of the oriental, the mask can be better attached to the nose bridge of the oriental, and the protection performance is enhanced.

Preferably, the distance (L shown in fig. 8) between the highest point of the first protrusion 211 and the highest point of the second protrusion 212 is 40.1887mm-60.734mm, and the shortest distance in the width direction of the first flap 2 from the lowest point of the recess 213 to the highest point of the first protrusion 211 or the highest point of the second protrusion 212 (H shown in fig. 8) is 4.4631mm-5.6213mm, which is a further improvement based on the range in the above embodiment, more conforming to the nose shape of the eastern person.

Preferably, the groove width L is 54.2mm in size, the groove depth H is 5.3mm in size, and the arc length (S shown in fig. 9) of the recess 213 is 55.55mm, and the inventors have found through research that setting the groove width L to 54.2mm in size, the groove depth H to 5.3mm in size, and the arc length S to 55.55mm in size, fits well with the bridge of the nose of the eastern person, and the sealing effect is good.

Further, as shown in fig. 3, the first convex portion 211 and the second convex portion 212 are both arc segments, and the radius of the arc segments is 15mm, so that the first convex portion and the second convex portion can be better attached to two sides of the bridge of the nose, and are convenient to process.

In some embodiments, as shown in fig. 3, the recess 213 includes a first circular arc segment 2131, a second circular arc segment 2132, and a third circular arc segment 2133 connected in sequence, wherein each of the first circular arc segment 2131 and the third circular arc segment 2133 protrudes in a direction toward the second side 22 (an upper direction as shown in fig. 1), and the second circular arc segment 2132 protrudes in a direction away from the second side 22 (a lower direction as shown in fig. 1).

Since the nose bridge has a protruding structure, the recess is entirely in the shape of an arc that is concave toward the second side, and therefore, in the above-described embodiment, the first arc segment and the third arc segment are convex toward the lower direction as shown in fig. 1, and the second arc segment is disposed between the first arc segment and the third arc segment to mainly contact with the tip of the nose bridge. But because the height and the shape of nose bridge are different, set up the second circular arc section as the top direction bulge as shown in figure 1, the laminating of recess and nose bridge can be better guaranteed, the sealed guard action of gauze mask has further been improved.

In some embodiments, the first protrusion 211, the first circular arc segment 2131, the second circular arc segment 2132, the third circular arc segment 2133, and the second protrusion 212 are sequentially tangent. So set up, smooth transition between each circular arc section, the whole linearity of first side 21 is also more smooth, and has also played the positive role to the sealed effect of strengthening gauze mask bridge of the nose position.

Specifically, as shown in fig. 3 and 9. The radii of the first and

third arc segments

2131, 2133 are both 46.34mm, the arc lengths of the first and

second arc segments

2131, 2132 are both 20.27mm, the radius of the second arc segment 2132 is 50mm, and the arc length of the second arc segment 2132 is 2.69 mm.

It is understood that the present application is not limited to the embodiment shown in fig. 2, for example, in other embodiments, as shown in fig. 6, the concave portion 213 is provided as a single arc segment, and protrudes toward the second side surface 22, the radius of the arc segment is 60.19mm, and both ends of the arc segment are tangent to the first convex portion 211 and the second convex portion 212 respectively.

Compared with the multi-section arc concave structure, the concave structure has the advantages that although the concave structure is lower in fit degree with the nose bridge, the wiring mode is simple, the production and the processing are convenient, and the processing cost is reduced.

In some embodiments, as shown in fig. 5, the first side 21 of the first flap 2 further has a first diagonal segment 214 and a second diagonal segment 215, one end of the first diagonal segment 214 is connected to the first protrusion 211, the other end of the first diagonal segment 214 is connected to the cover by a first bend 216, one end of the second diagonal segment 215 is connected to the second protrusion 212, and the other end of the second diagonal segment 215 is connected to the cover 1 by a second bend 217.

In some specific embodiments, in the closed position, in the projection of the first flap 2 on the inner side of the cover 1, an angle between a connecting line of a highest point of the first convex portion and a highest point of the second convex portion and the first diagonal segment 214 is 15 degrees, and an angle between a connecting line of a highest point of the first convex portion and a highest point of the second convex portion and the second diagonal segment 215 is 15 degrees.

As shown in fig. 8, in some embodiments, the maximum length of the first flap 2 is 187.7mm, and the length of the cover 1 is 218mm, where the length direction refers to the left-right direction shown in fig. 1, the maximum length of the first flap 2 refers to the straight distance from the leftmost end to the rightmost end of the first flap 2 in the left-right direction, and similarly, the length of the cover 1 refers to the straight distance from the leftmost end to the rightmost end of the cover 1 in the left-right direction.

It can be understood that the first convex part is connected with the inner side surface of the cover body through the first oblique line segment and the first bending part in sequence, and the second convex part is connected with the inner side surface of the cover body through the second oblique line segment and the second bending part in sequence. The straight line section is a part jointed with the face, the bending part is a transition part from the straight line section to the cover body, and the straight line sections are all provided with specific angles (such as the 15-degree included angle) so as to ensure that the first oblique line section, the second oblique line section and the face have better jointing degree, further adapt to the face structure and ensure the jointing degree of the first folding piece and the face.

In some embodiments, the first flap 2 includes a first body portion 23 and a first folded portion 24, the first body portion 23 is attached to the inner side surface of the cover 1, the first folded portion 24 is attached to the first body portion 23 and is foldable relative to the first body portion 23, and the first folded portion 24 includes the first side surface 21 of the first flap 2. As shown in fig. 1, the connection between the first body portion 23 and the first folded portion 24 is adjacent to the upper edge of the cover 1.

Specifically, as shown in fig. 4, the whole cover body 1 is shuttle-shaped, the width of the cover body is gradually reduced from the middle to two ends, the upper edge and the lower edge of the cover body 1 are both arc-shaped, and two ends of the cover body 1 are used for connecting with hangers. The junction of the first body portion 23 and the first folded portion 24 is substantially arc-shaped and is consistent with the arc shape of the upper edge of the cover 1.

First, the first body part is jointed and connected with the inner side surface of the cover body, and the connection mode is very stable. The connecting line of the first turnover part and the cover body is distributed in an arc shape, so that when the cover body is in a plane state, the first turnover part and the first body part are simultaneously attached to the inner side surface of the cover body, when the two ends of the cover body bend towards the inner side surface of the cover body, the first turnover part is turned over from a closed position to an open position, and at the moment, the mask can be worn on the face and well attached.

In some embodiments, as shown in fig. 1, the mask further includes a second flap 3, the second flap 3 is disposed on an inner side surface of the mask body 1 and can be folded between a closed position and an open position, the second flap 3 and the first flap 2 are arranged opposite to each other in a width direction of the first flap 2, in the closed position, the second flap 3 is attached to the inner side surface of the mask body 1, and in the open position, at least a portion of the second flap 3 is away from the inner side surface of the mask body 1.

As shown in fig. 7, the second flap 3 is provided at the upper and lower positions of the cover body so as to oppose the first flap 2, and is similar in structure except that the lower side surface of the second flap 3 is different from the first side surface 21 of the first flap 2, and the first side surface 21 has a convex portion and a concave portion, so that the closed position and the open position of the second flap 3, and the closed position and the open position of the first flap 2 are the same.

The second folding piece is used for guaranteeing the sealing effect of the mask and the chin position, and compared with the mode that the mask body is directly attached to the chin position, the effect of the second folding piece is obviously better, in order to further improve the sealing effect of the second folding piece, the lower side surface of the second folding piece is of a smooth curved surface structure, as shown in fig. 7, the second folding piece is in a closed position, and in the projection of the inner side surface of the mask body, the lower side surface of the second folding piece is arc-shaped.

In some embodiments, the second flap 3 includes a second body portion 31 and a second folded portion 32, the second body portion 31 is attached to the inner side surface of the cover 1, and the second folded portion 32 is connected to the second body portion 31 and is foldable relative to the second body portion 31. The beneficial effect of this structure is the same as the first folding piece 2, and the description is omitted.

In the following, the statistics and calculation processes made by the applicant are described in relation to each other.

Table 1 shows the dimensions of the contact area between the nose bridge and the mask of the chinese, which are obtained by performing a face shape survey on the chinese, including two data, i.e., the nasal width (S1) and the nasal height (H1).

Table 1

	Width of nasal cavity S1	High nasal H1
			Mean value of	31.3	15.0
Maximum value	45.0	27.1
			Minimum value	20.1	8.1

According to the data of the width and height of the middle nose in the table 1, according to the formula

Data for the arc length S2 of the groove around the bridge of the nose was calculated as shown in table 2.

Table 2

	Mean value of	Maximum value	Minimum value
				Arc length S2	43.355	70.446	25.816

According to the above embodiment, the arc length S, the groove width L and the groove depth H are calculated to obtain the ratio of the groove width L to the arc length S

Of groove depth H and arc length SRatio of

The arc length S is 55.55mm, and the groove width L6 is 54.2 mm; the groove depth H is 5.3 mm;

ratio of groove width to arc length

L6＝0.9757*S；

Ratio of groove depth to arc length

H＝0.09541*S；

From the above ratios, a range of groove sizes for the groove structure was calculated, as shown in table 3.

Table 3

	Mean value of	Maximum value	Minimum value
				Groove width L6	42.3015	68.734	25.1887
Groove depth H	4.1365	6.7213	2.4631

From table 3, the dimensional ranges for the groove width L and the groove depth H are derived:

25.1887 is less than or equal to the groove width L6 is less than or equal to 68.734;

2.4631 is less than or equal to 6.7213;

the applicant of the present application performed comprehensive tests on masks with different sizes, tables 4 and 5 are test data of the embodiment of the present invention, and tables 6 and 7 are test data of masks with the same groove size but different routing methods.

In the following table, the meaning of the various data is:

filtration efficiency PPE%: under a certain gas flow, the mask has the filtering efficiency on the non-oily particles;

ventilation resistance pa: the air suction resistance of the mask is realized under a certain air flow;

adhesion: the mask design should provide good fit, and the total fit factor of the mask should be no less than 100;

table 4

Table 5

Table 6

Table 7

The applicant of the present application also tested five kinds of masks having different groove widths L and groove depths H, with the following test results: the test data of the mask are shown in tables 8 and 9, where the groove width is 42.3015mm and the groove depth is 4.1365 mm.

Table 8

Table 9

The dimensions of the groove are: the test data of the mask are shown in tables 10 and 11, where the groove width is 40.1887mm and the groove depth is 4.4631 mm.

Table 10

Table 11

The dimensions of the groove are: the groove width was 60.734mm, the groove depth was 5.6213mm, and the mask test data are shown in tables 12 and 13.

Table 12

Table 13

The mask dimensions were 25.1887mm for the groove width and 2.4631mm for the groove depth, and the test data for the mask are shown in tables 12 and 13.

Table 14

Table 15

The test data of the mask with the dimensions of 68.734mm for the groove width and 6.7213mm for the groove depth are shown in tables 12 and 13.

Table 16

Table 17

The applicant of the present application also tested the parameters associated with the KF94 mask on the market, and the test data are shown in tables 18 and 19:

table 18

Table 19

The KF94 mask data was compared with the data of the masks in the examples of the present invention, as shown in table 20 (the data in table 20 are average data):

table 20

From the above data, we can find that the mask of the embodiment of the present invention has overall better performance than KF 94.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A mask, comprising:

a cover body;

a first flap provided on an inner side surface of the cover and foldable between a closed position and an open position, the first flap including a first side surface and a second side surface that are arranged opposite to each other in a width direction thereof, the first flap being attached to the inner side surface of the cover in the closed position, at least a part of the first flap being away from the inner side surface of the cover in the open position so that the first side surface of the first flap faces inward,

the first side face of the cover body is a curved face and is provided with a first convex portion, a second convex portion and a concave portion located between the first convex portion and the second convex portion, the concave portion is approximately in an arc shape recessed towards the second side face, the distance between the highest point of the first convex portion and the highest point of the second convex portion is 25.1887mm-68.734mm, and the shortest distance between the lowest point of the concave portion and the highest point of the first convex portion or the highest point of the second convex portion in the width direction of the first folding piece is 2.4631mm-6.7213 mm.

2. The mask of claim 1 wherein the distance between the highest point of said first convex portion and the highest point of said second convex portion is 40.1887mm-60.734mm, and the shortest distance between the lowest point of said concave portion and the highest point of said first convex portion or the highest point of said second convex portion in the width direction of said first flap is 4.4631mm-5.6213 mm.

3. The mask of claim 2 wherein the distance between the highest point of said first convex portion and the highest point of said second convex portion is 54.2mm, and the shortest distance from the lowest point of said concave portion to the highest point of said first convex portion or the highest point of said second convex portion in the width direction of said first flap is 5.3 mm.

4. The mask of claim 3 wherein said first and second protrusions are both circular segments, said circular segments having a radius of 15 mm.

5. The mask of claim 4 wherein said recess comprises a first arc segment, a second arc segment, and a third arc segment connected in series, said first arc segment and said third arc segment both projecting in a direction toward said second side, said second arc segment projecting in a direction away from said second side.

6. The mask of claim 5 wherein said first convex portion, said first arc segment, said second arc segment, said third arc segment, said second convex portion are sequentially tangent.

7. The mask of claim 5 wherein the radius of each of said first arc segment and said third arc segment is 46.34mm, and the arc length of each of said first arc segment and said third arc segment is 20.27 mm; the radius of second circular arc section is 50mm, the arc length of second circular arc section is 2.69 mm.

8. The mask of claim 3 wherein said concave portion is a circular arc segment having a radius of 60.19mm, and wherein said concave portion is tangent to said first convex portion and said second convex portion at opposite ends thereof.

9. The mask of any one of claims 1 to 8 wherein the first side of the first flap further comprises a first diagonal segment and a second diagonal segment, wherein one end of the first diagonal segment is tangent to the first convex portion, the other end of the first diagonal segment is connected to the mask body by a first bend, one end of the second diagonal segment is tangent to the second convex portion, and the other end of the second diagonal segment is connected to the mask body by a second bend.

10. The mask of claim 9 wherein said first diagonal segment and said second diagonal segment are inclined at an angle of 15 °.