Cup lid assembly

Abstract

The present invention discloses a cup lid assembly, which is to provide a liquid discharge opening on the cup lid, and the liquid discharge opening can be opened or closed through turning operation made on the cup lid. The cup lid assembly includes a cup receiving body that can receive and cover a cup brim of a cup, a covering lid to cover the cup receiving body, and a drive sheet that is located between the cup receiving body and covering lid for opening or closing the liquid discharge opening. The present invention features on simple structure, which means that all the relative cup-lid components can be assembled through locking or pivotal joining without employing any fastening member for fastening operation. Therefore, the present invention can be simple in structure and handy in assembling, and the liquid discharge opening can be easily opened or closed through simple turning operation.

Description

FIELD OF THE INVENTION

The present invention relates to a cup lid assembly or a drinking-cup lid assembly and, more particularly, to a cup lid assembly that provides a liquid discharge opening to be opened or closed through turning operation made on the cup lid.

BACKGROUND OF THE INVENTION

Fast food eating has been a common life style for many busy people around the world. People often find time to enjoy their fast food while they are walking or driving. However, one thing may bother them is that beverages in their cups may be splashed or spilt during walking or driving, which may smear their clothes or cars. Therefore, it is always an important issue to design a cup lid that can be easily opened for drinking as well as securely closed when not in use while the cup user is in motion.

U.S. Pat. No. 6,010,029 entitled “Container Lid Assembly” will be discussed below as an example of the prior art. The technical contents of this patent are summed up as follows:

The container lid assembly includes a rotary cap 10, a lid body 20, and a control device 40, wherein a drive post 13 is provided extending from the bottom of the rotary cap 10, whereas a control block 14 with a threaded bore 15 is provided extending from the bottom of the drive post 13;

an inner thread 221 extending downward from the inner periphery of the lid body 20 is to be received by an enlarged lower portion 22 located at the top of a container body 68; besides, a liquid discharge slot 25 and a stub 26 are provided penetrating through the lid body 20, and a lug 24 is provided downward from the middle of the discharge slot 25 and stub 26; also, an annular flange 27 is provided extending from the inner bottom of the lid body 20, and a plurality of concave openings 271 is provided on the annular flange 27; and

an upper strip 50 and a lower strip 60 are included in the control device 40 in a way that the upper strip 50 can be mounted on the top of lower strip 60 for overlapping; besides, a locking hole 52 is provided in the middle of the upper strip 50, whereas a square locking hole 62 is correspondingly provided in the middle of the lower strip 60; also, a reduced neck 53 is provided at each of the two sides of the upper strip 50, extending outwardly thereon to form a first end portion 55 and a second end portion 56, wherein a positioning block 57 and a sealing plug 561 are further provided at the end of the first end portion 55 and the second end portion 56 respectively; in addition, a sealing gasket 58 is provided on the positioning block 57, and a press block 541 is provided upwardly from the front side of the first end portion 55 and the second end portion 56 respectively.

To operate, the rotary cap 10 can be received by and positioned on the top of the lid body 20; also, the control block 14 under the drive post 13 can firstly go into the passage 241 of the lug 24, then go through a square hole 310 of a cushion 31, afterwards go through the hole formed by the locking hole 52 and square locking hole 62 from a joining made by the upper strip 50 and lower strip 60, and finally go into a recess 66 of a connector 65, while a locking screw 67 will be put into the bore 650 on the connector 65 to fasten the control device 40; furthermore, the reduced neck 53 of the upper strip 50 is designed to be pushed against by the resilient force generated by the lower strip 60, and the generated force enables the press block 541 of the upper strip 50 located closely adjacent to the concave openings 271 of annular flange 27 to make a sliding movement when the rotary cap 10 is turned by the user so as to achieve the purpose of opening or closing the liquid discharge slot 25 and stub 26.

To conclude, the aforementioned patent has mainly improved two drawbacks of its prior arts. One of them is to improve the fatigue that may be caused by the spring in the prior arts, and the other is to change the way of opening the liquid discharge slot 25 by simply turning the rotary cap 10 instead of continuously pressing the liquid discharge slot 25. Nevertheless, three drawbacks remain to be unsolved in this prior invention, which will be listed as follows:

• • 1) The members that construct the control device 40 of the patent are very complicated in structure; as a result, manufacturing procedures such as mold opening, producing, and assembling will become more troublesome, which in turn may increase the production cost and lower the efficiency of production.
  • 2) The opening and closing mechanism of the liquid discharge slot 25 is operated by a resilient force generated by the lower strip 60 in a way of pushing against the upper strip 50 when both strips are joined together; therefore, the opening and closing mechanism of the liquid discharge slot 25 is operated by flexible-textured members instead of solid-textured members; as a result, the flexible-textured members may eventually result in fatigue and cause a failure in performing sealing function.
  • 3) From the control device 40 of this patent, it can be judged that the upper and lower strips 50 and 60 and locking screw 67 are all made of metal. In fact, the lower strip 60 must be a sheet of metal spring to meet the requirement of good elastic strength for pushing the upper strip 50 to lean closely to the concave openings 271 for sliding movement so as to open or close the liquid discharge slot 25 and stub 26. However, shaking motion or steaming phenomenon generated by the liquid inside a liquid container may cause the metal sheet to become rusted, which is not sanitary once if the liquid contacts the rusted portion.

Therefore, the present invention is designed to solve the afore-mentioned problems, including high manufacturing cost, low production efficiency, the failure to entirely seal the liquid discharge slot, and the sanitary problem caused by the rusted metal sheet.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide a cup lid assembly suitable for easy and fast assembling through locking and pivotal joining method, wherein a solid-textured member of the cup lid can generate a force pressing on the liquid discharge opening upon receiving a turning force made on the cup lid, allowing the liquid discharge opening to be entirely sealed.

According to the present invention, the cup lid assembly includes a cup receiving body, a covering lid, and a driver sheet, wherein the cup receiving body is used to cover the cup brim of a cup body, and a liquid discharge opening and a vent are provided penetrating through the cup receiving body; besides, an elastic body is provided in the middle of the cup receiving body, while a push block and a halt block are separately provided, extending from the cup receiving body thereon, located at each side of an imaginary line drawing along the liquid discharge opening and the elastic body; also, the covering lid can be pivotally received by the rim of the cup receiving body and can be turned by turning operation when it is placed on the cup receiving body; besides, a drinking opening is provided penetrating through the covering lid and can be aligned with the liquid discharge opening when the cup receiving body is turned by turning operation; also, an axle is provided extending from a position corresponding to the elastic body and located at the bottom of the covering lid, and two guide portions are symmetrically provided from the axle; moreover, a releasing slot and a press-against section are provided on the guide portion, wherein the releasing slot is connected to one end of the press-against section and also forms an arch-shaped angle, whereas an actuating block is provided at the other end of the releasing block; on the other hand, a hinder block is provided at the other end of the press-against section; as to the drive sheet, an anti-liquid-flow portion and an anti-air-flow portion are provided extendedly from the drive sheet thereon, corresponding to the locations of the liquid discharge opening and the vent respectively; besides, a pivot-connecting portion is provided extending from the center of the drive sheet, to be pivotally connected to the axle as well as to be pushed by the elastic body for getting close to the covering lid.

To operate, when the covering lid is turned clockwise, the turning force imposing on the solid-textured object of the press-against section may push the drive sheet to make a position-shift downwardly, which in turn may enable the anti-liquid-flow portion to be tightly plugged into the liquid discharge opening whereas the anti-air-flow portion to be tightly plugged into the vent; in contrast, when the covering lid is turned anticlockwise, the drive sheet will detach from the press-against section in a manner that the elastic body will press against the pivot-connecting portion of the drive sheet, allowing the drive sheet to be located on the releasing slot, which in turn may enable the anti-liquid-flow portion and the anti-air-flow portion to be detached from the liquid discharge opening and the vent respectively for liquid outflow.

To sum up, the present invention is not only very simple in its structure but also very handy in assembling, which in turn can lower the production cost, entirely seal the liquid discharge opening, and assure a hygienic in-cup environment when the cup lid is in use because there is no metal can be touched by the liquid in the cup body of the present invention.

The objects and technical contents of the present invention will be better understood through the description of the following embodiments with reference to the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective diagram illustrating an exploded top view of the cup lid assembly according to the present invention.

FIG. 2 is a schematic perspective diagram illustrating an exploded bottom view of the cup lid assembly according to the present invention.

FIG. 3 is a schematic sectional view of the cup lid assembly according to the present invention.

FIG. 4A is a schematic diagram illustrating that the liquid discharge opening of the cup lid of the present invention is in an opening state.

FIG. 4B is a schematic diagram illustrating that the covering lid showed in FIG. 4A is in operation.

FIG. 4C is a schematic diagram illustrating that the covering lid showed in FIG. 4B is still in a continuous operation.

FIG. 5A is a schematic diagram illustrating that the covering lid showed in FIG. 4C is operated in a reverse direction.

FIG. 5B is a schematic diagram illustrating that the covering lid showed in FIG. 5A is still operating in a reverse direction.

FIG. 6 is a schematic diagram illustrating another aspect of the elastic body of the cup lid assembly of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1, 2, and 3 are schematic diagrams that illustrate an exploded top view, an exploded bottom view, and a side elevation view of the cup lid of the present invention respectively. Referring to FIGS. 1, 2, and 3, the cup lid assembly includes a cup receiving body 3, a covering lid 4, and a drive sheet 5. Besides, a cup-receiving portion 38 is located at the inner-wall of the bottom of cup receiving body 3, corresponding to as well as being received by the cup brim 61 for joining to the cup body 6. In addition, a liquid discharge opening 31 and a vent 32 are provided penetrating through the cup receiving body 3, and a recess 311 is provided at the edge of the liquid discharge opening 31 whereas another recess 321 is provided at the edge of the vent 32. Also, an elastic body 33 is provided in the middle of the cup receiving body 3. A push block 34 and a halt block 35 are separately provided, extending from the cup receiving body 3 thereon, and located at each side of an imaginary line drawing along the liquid discharge opening 31 and elastic body 33; besides, an accommodation slot 37 is upwardly extended from the middle of the cup receiving body 3 for accommodating the elastic body 33. Also, a cover receiving portion 36 is provided along the outer rim of the cup receiving body 3, whereas at least one cover joining portion 45 is formed in a way that its center is a hole, extending along the periphery of the covering lid 4 and corresponding to the cover receiving portion 36 for pivotally joining to the cover receiving portion 36 at the rim of the cup receiving body 3, so that the covering lid 4 can be turned when it is placed on the cup receiving body 3. In addition, a drinking opening 41 is provided penetrating through the covering lid 4; when the cup receiving body 3 is turned by a user, the drinking opening 41 will be at a position corresponding to the liquid discharge opening 31. Also, an axle 42 is provided extending from the bottom of the covering lid 4, corresponding to the elastic body 33. Taking the axle 42 as a dividing line, two guide portions 43 are symmetrically provided at the two sides of the line, and a releasing slot 431 and a press-against section 432 are located on each guide portion 43. The releasing slot 431 is connected to the press-against section 432 and forms an arch-shaped angle 433, and an actuating block 434 is provided at the other end of the releasing slot 431 whereas a hinder block 435 is provided at the other end of the press-against section 432. On the other hand, an anti-liquid-flow portion 51 and an anti-air-flow portion 52 are provided extending from the drive sheet thereon, corresponding to the positions where the liquid discharge opening 31 and vent 32 are located respectively. Besides, a big plug 511 made of flexible material is sleeved on the anti-liquid-flow portion 51, wherein a first protrusion 512 is provided on the big plug 511 to be corresponding to the first recess 311, and through plugging-in made between the first protrusion 512 and the first recess 311, the liquid discharge opening 31 can be entirely sealed. Likewise, a small plug 521 made of flexible material is sleeved on the anti-air-flow portion 52, wherein a second protrusion 522 is provided on the small plug 521 to be corresponding to the second recess 321, and through plugging-in made between the second protrusion 522 and the second recess 321, the vent 32 can be entirely sealed. Also, a pivot-connecting portion 53 is provided extending from the middle of the drive sheet 5, to be pivotally connected to the axle 42 as well as to be pushed by the elastic body 33 for leaning closely to the covering lid 4.

Next, referring to FIG. 4A, which is a schematic diagram illustrating that the liquid discharge opening of the cup lid of the present invention is in an opening state, the cup lid assembly is shown by a side elevation view and a top view in order to obtain a best description result, in which the position of covering lid 4 is expressed by dash-dot lines in the top-viewed diagram. As shown in FIG. 4A, when the drive sheet 5 is located in the releasing slot 431 and its pivot-connecting portion 33 is being pushed against by the elastic body 33, the anti-liquid-flow portion 51 and the anti-air-flow portion 52 will be away from the liquid discharge opening 31 and vent 32 respectively, and the drinking opening 41 will be aligned with the liquid discharge opening 31, ready for the liquid in the cup body 6 to flow out from the liquid discharge opening 31.

Also, referring to FIG. 4B, which is a schematic diagram illustrating that the covering lid showed in FIG. 4A is in operation, the cup lid assembly is also shown by a side elevation view and a top view in order to obtain a best description result, in which the position of covering lid 4 is expressed by dash-dot lines in the top-viewed diagram. As shown in FIG. 4B, when the liquid discharge opening 31 and vent 32 are to be closed for stopping liquid in the cup body (not shown) from flowing out, the covering lid 4 can be turned clockwise. As soon as this action is made, the drive sheet 5 located in the releasing slot 351 will be pushed against by the arch-shaped angle 433 and turned along with the covering lid 4 until the push block 34 reaches the side of the drive sheet 5 for pressing against it.

As the turning operation continues, the cup lid assembly will move into another state, which is shown in FIG. 4C, illustrating that the covering lid showed in FIG. 4B is still in a continuous operation. Similarly, the cup lid assembly is shown by a side elevation view and a top view in order to obtain a best description result, in which the position of covering lid 4 is expressed by dash-dot lines in the top-viewed diagram. As shown in FIG. 4C, when the covering lid 4 is continuously being turned by turning operation, the push block 34 will push the side face of drive sheet 5 located in the releasing slot 431, and because the turning force is larger than the press-against force from the arch-shaped angle 433, the drive sheet 5 will then slide into the hinder block 435 located at the press-against section 432 of the guide portion 43 for positioning through guidance made by the arch-shaped angle 433. Under such circumstances, the drive sheet 5 will be located at the press-against section 432 that has elevation difference from its prior location at releasing slot 431. Because of the elevation difference, the drive sheet 5 will move downward and press against the elastic body 33 in a way that the liquid discharge opening 31 and vent 32 located at the cup receiving body 3 will be entirely blocked by the anti-liquid-flow portion 51 and anti-air-flow portion 52 respectively located at the drive sheet. By so doing, the liquid in the cup body 6 (not shown) can be stopped from flowing out, and the drinking opening 41 will withdraw from the position that corresponds to the liquid discharge opening 31.

Furthermore, referring to FIG. 5A, which illustrates that the covering lid showed in FIG. 4C is operated in a reverse direction, the cup lid assembly is again shown by a side elevation view and a top view in order to obtain a best description result, in which the position of covering lid 4 is expressed by dash-dot lines in the top-viewed diagram. In addition to FIG. 5A, FIG. 5B further illustrates that the covering lid showed in FIG. 5A is still operating in a reverse direction. Also, similar to FIG. 5A, the dash-dot lines are also used for illustrating the position of covering lid 4. As shown in FIGS. 5A and 5B, when a user's intension is to open the liquid discharge opening 31 and vent 32, the covering lid 4 can be turned anticlockwise. Under such circumstances, the drive sheet 5 will not move along with the covering lid 4 because it is being pressed against by the resilience generated by the elastic body 33. In fact, the drive sheet 5 will slide along the press-against section 432 of guide portion 43 and move into the releasing slot 351 when the covering lid 4 is turned by turning operation, so that the drive sheet can make a position shift upwardly, enabling the anti-liquid-flow portion 51 and anti-air-flow portion 52 to upwardly open the liquid discharge 31 and vent 32 (as shown in FIG. 5A) respectively. At this moment, if the covering lid 4 is being continuously turned, the actuation block 434 will push against the drive sheet 5, and the resilient force generated by the elastic body 33 will impose on the drive sheet 5, pushing it to the hinder block 35 for a stop, whereas the anti-liquid-flow portion 51 and anti-air-flow portion 52 on the drive sheet 5 will withdraw from the liquid discharge opening 31 and vent 32 on the cup receiving body 3 respectively. By doing so, the liquid discharge opening 31 can be aligned with the drinking opening 41 (as shown in FIG. 5B) for the liquid in the cup body 6 (not shown) to flow out. Therefore, the present invention is not only very simple in its structure but also very handy in assembling, which in turn can lower the production cost, entirely block the liquid discharge opening 31, and assure a hygienic in-cup environment when the cup lid is in use because there is no metal can be touched by the liquid in the cup body.

Finally, FIG. 6 is a schematic diagram illustrating another aspect of the elastic body of the cup lid of the present invention. This aspect of elastic body is different from that of in the above-mentioned embodiment in the cup receiving body 3′ because there is an accommodation slot 37′ concavely provided in an upward direction in the middle of the cup receiving body 3′. The accommodation slot 37′ is used to accommodate the pivot-connecting portion 53′ instead of the elastic body 33′ when the drive sheet 5′ is having a downward motion. In addition, an elastic body 33′ such as a spring will be provided in the axle 42 extending from the bottom of the covering lid 4, whereas a pivot-connecting portion 53′ extending from the middle of the drive sheet 5′ will be pivotally connected to the axle 42. The bottom of the pivot-connecting portion 53′ is a closed end and is connected to the elastic body 33 by hook connection so that the drive sheet 5′ can be pulled by the elastic body 33′ to get close to the covering lid 4. Therefore, the aforementioned functions shown in FIG. 3 can be achieved as well.

The embodiments above are only intended to illustrate the present invention; they do not, however, to limit the present invention to the specific embodiments. Accordingly, various modifications and changes may be made without departing from the spirit and scope of the present invention as described in the following claims.

Claims

1. A cup lid assembly, provided at the brim of a cup body to be turned by opening and closing operation, including

a cup receiving body, to cover the brim of a cup, wherein a liquid discharge opening and a vent are provided penetrating through the cup receiving body; besides, an elastic body is provided in the middle of the cup receiving body, while a push block and a halt block are separately provided, extending from the cup receiving body thereon, and located at each side of an imaginary line drawing along the liquid discharge opening and the elastic body; also, an accommodation slot is upwardly extended from the middle of the cup receiving body for accommodating the elastic body;

a covering lid, which is pivotally connected to the rim of the cup receiving body and can be turned by turning operation when it is placed on the top of the cup receiving body; a drinking opening is provided penetrating through the covering lid, capable of corresponding to the liquid discharge opening when the drinking opening is turned by turning operation made on the cup receiving body; an axle is provided extending from the bottom of the covering lid, corresponding to the position of the elastic body; taking the axle as a dividing line, two guide portions are symmetrically provided at two sides of the dividing line, and a releasing slot and a press-against section are located on each guide portion respectively, wherein the releasing slot is connected to one end of the press-against section and forms an arch-shaped angle, and an actuating block is located at the other end of the releasing slot whereas a hinder block is located at the other end of the press-against section; and

a drive sheet, wherein an anti-liquid-flow portion and an anti-air-flow portion are provided extending from the drive sheet thereon, corresponding to the positions where the liquid discharge opening and the vent are located respectively; also, a pivot-connecting portion is provided extending from the middle of the drive sheet, to be pivotally connected to the axle as well as to be pushed by the elastic body for leaning closely to the covering lid;

to operate, when the drive sheet located in the press-against section makes a position-shift downwardly to press against the elastic body, the anti-liquid-flow portion can be tightly plugged into the liquid discharge opening whereas the anti-air-flow portion can be tightly plugged into the vent; in contrast, when the drive sheet located in the releasing slot is pressed against by the elastic body on the pivot-connecting portion of the drive sheet, the anti-liquid-flow portion and the anti-air-flow portion can be detached from the liquid discharge opening and the vent respectively; thus, the brim of the cup can be turned by opening and closing operation.

2. The cup lid assembly as claimed in claim 1, wherein a cup-receiving portion is located at the inner-wall of the bottom of the cup receiving body, corresponding to and being received by the cup brim for tight joining to the cup body.

3. The cup lid assembly as claimed in claim 1, wherein a cover receiving portion is provided along the outer rim of the cup receiving body, whereas at least one cover joining portion is provided corresponding to the cover receiving portion for pivotal joining, and through the pivotal connection between the cover joining portion and the cover receiving portion, the covering lid can be turned when it is placed on the cup receiving body.

4. The cup lid assembly as claimed in claim 3, wherein the cover receiving portion is formed in a way that its center is a hole.

5. The cup lid assembly as claimed in claim 1, wherein a first recess is provided at the edge of the liquid discharge opening on the cup receiving body, a big plug made of flexible material is sleeved on the anti-liquid-flow portion on the drive sheet, wherein a first protrusion is provided on the big plug to be corresponding to the first recess, and through joining made between the first protrusion and the first recess, the liquid discharge opening can be entirely sealed.

6. The cup lid assembly as claimed in claim 1, wherein a second recess is provided at the edge of the vent on the cup receiving body; besides, a small plug made of flexible material is sleeved on the anti-air-flow portion, wherein a second protrusion is provided on the small plug to be corresponding to the second recess, and through joining made between the second protrusion and the second recess, the vent can be entirely sealed.

7. A cup lid assembly, provided at the brim of a cup body to be turned by opening and closing operation, including

a cup receiving body, to cover the brim of a cup, wherein a liquid discharge opening and a vent are provided penetrating through the cup receiving body; besides, a push block and a halt block are separately provided, extending from the cup receiving body thereon, and located at each side of an imaginary line drawing along the liquid discharge opening and the elastic body; also, an accommodation slot is concavely provided in an upward direction in the middle of the cup receiving body;

a covering lid, which is pivotally connected to the rim of the cup receiving body and can be turned by turning operation when it is placed on top of the cup receiving body; a drinking opening is provided penetrating through the covering lid, capable of corresponding to the liquid discharge opening when the drinking opening is turned by turning operation made on the cup receiving body; an axle is provided extending from the bottom of the covering lid, and an elastic body is provided in the axle; taking the axle as a dividing line, two guide portions are symmetrically provided at two sides of the dividing line, and a releasing slot and a press-against section are located on each guide portion respectively, wherein the releasing slot is connected to one end of the press-against section and forms an arch-shaped angle, and an actuating block is located at the other end of the releasing slot whereas a hinder block is located at the other end of the press-against section; and

a drive sheet, wherein an anti-liquid-flow portion and an anti-air-flow portion are provided extending from the drive sheet thereon, corresponding to the positions where the liquid discharge opening and the vent are located respectively; also, a pivot-connecting portion is provided extending from the middle of the drive sheet, to be pivotally connected to the axle as well as to be pulled by the elastic body for leaning closely to the covering lid; in addition, when the drive sheet is moving downward, the accommodation slot can accommodate the pivot-connecting portion;

to operate, when the drive sheet located in the press-against section makes a position-shift downwardly to press against the elastic body, the anti-liquid-flow portion can be tightly plugged into the liquid discharge opening whereas the anti-air-flow portion can be tightly plugged into the vent; in contrast, when the drive sheet is pulled back to the releasing slot by the elastic body, the anti-liquid-flow portion and the anti-air-flow portion can be detached from the liquid discharge opening and the vent respectively; thus, the brim of the cup can be turned opening and closing.

8. The cup lid assembly as claimed in claim 7, wherein a cup-receiving portion is located at the inner-wall of the bottom of the cup receiving body, corresponding to and being received by the cup brim for tight joining to the cup body.

9. The cup lid assembly as claimed in claim 7, wherein a cover receiving portion is provided along the outer rim of the cup receiving body, whereas at least one cover joining portion is provided corresponding to the cover receiving portion for pivotal joining, and through the pivotal connection between the cover joining portion and the cover receiving portion, the covering lid can be turned when it is placed on the cup receiving body.

10. The cup lid assembly as claimed in claim 9, wherein the cover receiving portion is formed in a way that its center is a hole.

11. The cup lid assembly as claimed in claim 7, wherein a first recess is provided at the edge of the liquid discharge opening on the cup receiving body, a big plug made of flexible material is sleeved on the anti-liquid-flow portion on the drive sheet, wherein a first protrusion is provided on the big plug to be corresponding to the first recess, and through joining made between the first protrusion and the first recess, the liquid discharge opening can be entirely sealed.

12. The cup lid assembly as claimed in claim 7, wherein a second recess is provided at the edge of the vent on the cup receiving body, a small plug made of flexible material is sleeved on the anti-air-flow portion, wherein a second protrusion is provided on the small plug to be corresponding to the second recess, and through joining made between the second protrusion and the second recess, the vent can be entirely sealed.