Abstract:
An object of the present invention is to provide a food preservative container that is constructed such that when the container stored in a refrigerator is taken out of the refrigerator and is to be opened on a dining table, mere lifting up of a closure member with fingers gripping a finger grip makes it possible to achieve the operation of releasing the reduced pressure state inside the container and the operation of lifting up the closure member in a one-touch fashion. In a closure member attached with a finger grip portion and fitted over the opening of a container body, the finger grip portion includes a finger grip main body having a lower portion formed with an engagement portion that is inserted into a through-hole of the closure member while ensuring air communication through the through-hole, and a cylindrical outer cover portion formed from a flexible material and circumscribing the finger grip main body. The outer cover portion has an upper part intimately contacting the finger grip main body and a lower part abutting an upper surface of the closure member. When the flexible outer cover portion of the finger grip portion is gripped with fingers in order to lift up the closure member, the lower part of the outer cover portion of the finger grip portion partially detaches from the upper surface of the closure member thereby releasing hermetic pressure-contact with the closure member.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a food preservative container comprising a container body and a closure member fitted over the container body so as to close an opening of the container body, the closure member having a peripheral edge that can be hermetically fitted to the container body.  
           [0003]    2. Description of the Related Art  
           [0004]    A conventional food preservative container comprises a container body and a closure member attached with a finger grip portion and fitted over the container body so as to close an opening of the container body, the closure member having a peripheral edge that can be hermetically fitted to the container body (see Japanese Unexamined Utility Model Publication No. 1992-118349 for example). Such a conventional container has an advantage in that food put in the container can be kept in a very favorable condition from the viewpoint of food hygiene because communication with air between the outside and inside of the container is cut off.  
           [0005]    The conventional food preservative container, however, involves a problem in that when the container stored in a refrigerator is taken out of the refrigerator and is to be opened on a dining table, the closure member cannot be detached from the container body even if the user tries to lift up the closure member while gripping the finger grip because the pressure of air within the container is reduced.  
           [0006]    In attempt to solve this problem, the conventional container is provided with an openable and closable vent hole defined by the closure member which is opened when the container is to be opened. Such an arrangement, however, raises another problem in that the inconvenience arises of necessitating two operations in opening the closure, namely the operation of opening the vent hole and the operation of lifting up the closure member by the finger grip, thereby reducing the commercial value of the container.  
           [0007]    Further, the vent hole of the conventional container is not closed if the closure member is merely fitted over the container body. Therefore, it is possible that the container is stored in a refrigerator with the vent hole left open, resulting in a problem in that the conventional container may lose its hermetic sealing effect.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention is provided in order to solve the foregoing problems of the prior art.  
           [0009]    Accordingly, it is an object of the present invention to provide a food preservative container that is capable of keeping food contained in the container in a very favorable condition from the viewpoint of food hygiene by cutting off air communication between the outside and the inside of the container.  
           [0010]    Another object of the present invention is to provide a food preservative container that is constructed such that when the container  1  stored in a refrigerator is taken out of the refrigerator and is to be opened on a dining table, mere lifting of a closure member  3  with its finger grip portion  16  gripped with fingers causes a sealing portion  40  in a lower part of a outer cover portion  38  to be partially moved toward the center of the finger grip portion and detaches from the closure member  3  thereby releasing the hermetic pressure-contact with the closure member  3  even when the pressure of air  11  within the container is reduced and, hence, the operation of releasing the reduced pressure state inside the container and the operation of opening the closure by lifting up the closure member  3  can be achieved in a one-touch fashion.  
           [0011]    Yet another object of the present invention is to provide a food preservative container such that when the container  1  containing food therein is to be stored in the refrigerator, the operation of merely fitting the closure member  3  over a container body before storing the container  1  in the refrigerator causes the outer cover portion  38  of the finger grip portion attached to the closure member  3  to return to its original position by its own elasticity, so that the lower part  40  of the circumferentially extending outer cover portion  38  is brought into hermetic pressure-contact with the upper surface of the closure member  3 , thereby ensuring a hermetic seal effect, hence contributing to a reduction in the internal pressure of the container  1 .  
           [0012]    Still another object of the present invention is to provide a food preservative container such that when an unusual reduction in the internal pressure of the container stored in the refrigerator occurs, the lower part of the finger grip portion elastically moves to allow outside air to be introduced into the container thereby playing the role of a safety valve.  
           [0013]    Still yet another object of the present invention is to provide a food preservative container such that when the finger grip portion  16  attached to the closure member  3  is to be washed, the finger grip portion  16 , even if configured to cut off air communication in a usual state but to permit air communication when gripped with fingers, can be easily removed from the closure member  3  for washing by merely disengaging an engagement pawl  35  of an engagement portion  34 .  
           [0014]    Yet still another object of the present invention is to provide a hygienic finger grip portion  16  such that when the finger grip portion  16  is removed from the closure member  3  for washing, every part of a dent portion defined in an inside portion  24  of the outer cover portion  38  can be washed easily by raising the lower part of the outer cover portion  38  to make the inside of the outer cover portion  38  open to the outside.  
           [0015]    A further object of the present invention is to provide a food preservative container such that when the internal pressure of the container  1  containing food therein is unusually elevated due to heating, a seal member  42  extending circumferentially around the closure member  3  is capable of serving as a safety valve.  
           [0016]    Other objects and advantages of the present invention will readily become apparent from the following detailed description taken in connection with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    [0017]FIG. 1 is a longitudinal sectional view illustrating the relationship between a container body and a closure member;  
         [0018]    [0018]FIG. 2 is a plan view of the closure member;  
         [0019]    [0019]FIG. 3 is a back view of the closure member;  
         [0020]    [0020]FIG. 4 is a plan view showing a seal member;  
         [0021]    [0021]FIG. 5 is a sectional view along the line V-V in FIG. 4;  
         [0022]    [0022]FIG. 6(A) is a partially cutaway plan view showing a finger grip main body;  
         [0023]    [0023]FIG. 6(B) is a longitudinal sectional view along the line VI-VI;  
         [0024]    [0024]FIG. 6(C) is a back view of the finger grip main body;  
         [0025]    [0025]FIG. 7(A) is a plan view showing a grip outer cover portion;  
         [0026]    [0026]FIG. 7(B) is a longitudinal sectional view of the grip outer cover portion;  
         [0027]    [0027]FIG. 7(C) is a back view of the grip outer cover portion;  
         [0028]    [0028]FIG. 8 is a perspective view showing the finger grip main body and the grip outer cover portion;  
         [0029]    [0029]FIG. 9 is a fragmentary longitudinal sectional view illustrating a state where the grip outer cover portion is moved toward a central portion when the closure member is lifted up with the finger grip portion gripped with fingers;  
         [0030]    [0030]FIG. 10 is a sectional view along the line X-X in FIG. 9;  
         [0031]    [0031]FIG. 11 is a perspective view showing a state where the finger grip main body and the grip outer cover portion are assembled together (a state where a lower part  40  of the grip outer cover portion is turned up to extend above the finger grip main body);  
         [0032]    [0032]FIG. 12 is a longitudinal sectional view of the assembled state of the finger grip main body and the grip outer cover portion shown in FIG. 11;  
         [0033]    [0033]FIG. 13(A) is a sectional view, along the line E-E′, illustrating the relationship between a part of the closure member and the finger grip portion;  
         [0034]    [0034]FIG. 13(B) is a back view showing a part of the closure member and the finger grip portion;  
         [0035]    [0035]FIG. 14(A) is a plan view showing a part of the closure member from which the finger grip portion is removed;  
         [0036]    [0036]FIG. 14(B) is a sectional view along the line F-F′ in FIG. 14(A);  
         [0037]    [0037]FIG. 14(C) is a back view of the part of the closure member shown in FIG. 14(A);  
         [0038]    [0038]FIG. 15(A) is a plan view of the finger grip main body;  
         [0039]    [0039]FIG. 15(B) is a sectional view along the line G-G′ in FIG. 15(A);  
         [0040]    [0040]FIG. 15(C) is a back view of the finger grip main body shown in FIG. 15(A);  
         [0041]    [0041]FIG. 16(A) is a plan view of the grip outer cover portion;  
         [0042]    [0042]FIG. 16(B) is a sectional view along the line H-H′ in FIG. 16(A);  
         [0043]    [0043]FIG. 16(C) is a back view of the grip outer cover portion shown in FIG. 16(A);  
         [0044]    [0044]FIG. 17(A) is a sectional view, along the line K-K′, illustrating a state where the grip outer cover portion is moved toward a central portion when the closure member is lifted up with the finger grip portion gripped with fingers;  
         [0045]    [0045]FIG. 17(B) is a sectional view along the line J-J′ in FIG. 17(A); and  
         [0046]    [0046]FIG. 18 is a sectional view, along the line K-K′ in FIG. 17(B), illustrating a state where a negative pressure is provided in an introduction groove to cause an annular valve member to bend downwardly thereby allowing air to be supplied from the inside of the grip outer cover portion into the container body through the introduction groove.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0047]    Hereinafter, embodiments of the present invention will be described with reference to FIG. 1 through FIG. 12.  
         [0048]    Food preservative container  1  comprises a container body  2  and a closure member  3  attached with a finger grip portion, the closure member  3  being configured to fit over the container body  2  so as to close an opening  2   a  of the container body  2 . The closure member  3  has a peripheral edge  3   a  capable of being hermetically fitted to the container body  2 .  
         [0049]    Like a well-known conventional container body, the container body  2  is of any desired construction comprising a peripheral wall  6 , an upper edge  7 , a bottom portion  8 , a leg portion  9  and the like, all of which are formed using materials such as earthenware, porcelain, heat-resistant glass, metal, heat-resistant synthetic resin or the like selectively. The container body  2  defines a storage space  11  for storing food therein.  
         [0050]    There are many known prior-art means for hermetically, removably and openably fitting the peripheral edge  3   a  of the closure member  3  to the upper edge  7  of the container body  2 . Therefore, the food preservative container  1  of the present invention may utilize any desired one of such prior-art fitting means.  
         [0051]    [0051]FIG. 1 shows a characteristic construction of such fitting means. Reference numeral  10  designates a step portion formed on an inner peripheral portion of the container body  2  to circumferentially extend adjacent to the upper edge  7 , the step portion  10  forming a flat sealing surface providing a hermetic seal when abutted by a free edge  44  of a seal member  42 .  
         [0052]    As is well known in the art, a closure body  15  of the closure member  3  is formed using materials such as earthenware, porcelain, heat-resistant glass, metal, heat-resistant synthetic resin or the like selectively. The closure body  15  has a peripheral edge  17  circumscribed with an upwardly bulged reinforcement member. Reference numeral  18  designates an abutment portion adapted to abut the upper edge  7 . Reference numeral  20  designates a holding member for holding the seal member (packing  42 ), the holding member  20  defines a holding groove  21  for holding a base portion  43  of the seal member  42 .  
         [0053]    Reference numeral  22  designates an annular dent portion defined circumferentially around the finger grip portion  16  for receiving fingertips in the case where an upper surface of the finger grip portion  16  is lowered so as to be aligned flush with an upper surface of the closure member  3 . This dent portion  22  would be unnecessary if the upper surface of the finger grip portion  16  was located higher than the upper surface of the closure member  3 . Reference numeral  23  designates a sealing wall having a surface brought into hermetic pressure-contact with a lower part  40  of a grip outer cover portion  38 . The sealing wall  23  is in the form of an annular wall slightly protruding from the upper surface of the closure member  3  so as to match the outer peripheral shape of the lower part  40 . The sealing wall  23  has an annular top surface  23   a  that is a horizontal surface or an inclined surface having an outer peripheral edge higher than an inner peripheral edge for elastic pressure-contact with a lower surface of an annular step portion  40   a  forming the lower part of the outer cover portion  38 , thereby ensuring a sealing effect. Reference numeral  25  designates a hole border circumscribing a through-hole  19  defined centrally at the closure member  3 . A lower portion of the hole border  25  is formed into a step portion  25   a  allowing an engagement pawl  35  to be engaged therewith as shown in FIG. 9, while an upper portion  25   b  is configured to support a head member  30  of the finger grip main body  33 . Around the hole border  25  is defined a reduced-pressure space  24  which constantly communicates with the storage space  11  and of which the internal pressure is reduced when the container  1  is stored in a refrigerator in the same way as the internal pressure of the storage space  11 . This reduced-pressure space  24  also serves as a space allowing the sealing portion  40  forming the lower part of the grip outer cover  38  portion to retract, as clearly shown in FIG. 9. Reference numeral  26  designates vent holes extending radially outwardly from the through-hole  19  for allowing reliable communication between the storage space  11  and the reduced-pressure space  24 . Though air communication is sufficiently ensured by the provision of the through-hole  19  only, it is possible to provide a vent hole independently of the through-hole  19 , or the foregoing vent holes  26  for more sure communication between the inside and the outside of the closure member  3 .  
         [0054]    The finger grip portion  16  is attached to the closure member  3  by any known means, for example, by bonding the finger grip portion  16  as an integral part or comprising separate parts to the closure member  3  with any bonding means or fitting a disengageably engageable part into the through-hole  19  of the closure member  3  as shown in the drawings.  
         [0055]    The finger grip main body  33  of the finger grip portion  16  has a lower portion formed with a convex engagement portion  34 . The engagement portion  34  comprises, for example, a plurality of engagement members  34   a  (bifurcated or trifurcated member) defining a retractable space  36  therebetween and protruding downwardly from the lower portion of the finger grip main body  33 . Each of the engagement members  34   a  has a lower portion formed with the engagement pawl  35  disengageably engaging a lower edge  25   a  of the through-hole  19  of the closure member  3 . The engagement members  34   a  that can elastically open up or narrow the space therebetween are located in the through-hole  19  if they are inserted through the through-hole  19  so that the engagement pawls  35  at their free ends engage the step portion  25   a , while air communication through the retractable space  36  or the vent holes  26  is ensured. Thus, the finger grip main body  33  is removably attached to the closure member  3 .  
         [0056]    The finger grip main body  33  is formed by integrating the disk-like head member  30  and the engagement portion  34  bifurcated (defining a space  36  therebetween) to impart the two engagement pawls  35  with the ability to elastically open up or narrow the space therebetween with use of a rigid material such as ABS or polypropylene.  
         [0057]    It should be noted that FIG. 13 through FIG. 18 show other characteristic arrangements of means for attaching the finger grip portion  16  to the closure member  3 .  
         [0058]    The finger grip main body  33  is circumscribed with the grip outer cover portion  38  formed from a flexible airtight material (an elastic material having a restoring force such as silicone rubber or a heat-resistant synthetic resin partially having a predetermined elasticity). The outer cover portion  38  is wholly shaped cylindrically and has an upper part formed with an annular joint portion  39  that is hermetically and securely joined with a fitting step portion (joint portion)  37  formed circumferentially around the head member  30  by any desired means, for example, an adhesive or thermal fusion bonding. However, in the case where the finger grip main body  33  is formed from a material having such rigidity as to maintain its original shape in a normal condition, the outer cover portion  38  can be imparted with elasticity if it is made thinner and, as a result, it is possible to mold the finger grip main body  33  and the outer cover portion  38  integrally simultaneously using the same material.  
         [0059]    The structure for joining the annular joint portion  39  of the upper part of the outer cover portion  38  with a peripheral portion  30   a  of the head member  30  may be a joint structure wherein the peripheral portion  30   a  of the head member  30  is sandwiched between a partially turned-up annular member  38   a  indicated by a two-dot chain line which protrudes inwardly from the top of the outer cover portion  38  and a protruding member  39   a  formed below and spaced from the member  38   a , these members  38   a  and  39   a  elastically, removably and hermetically sandwiching the portion  30   a.    
         [0060]    It is also possible that entire scope  38   b , indicated by a two-dot chain line, of the upper part of the outer cover portion  38  is formed into a hat-like shape integral with the outer cover main body  38  using the same material so as to be elastically, hermetically and removably fitted over the finger grip main body  33  in a manner to completely cover the upper portion of the head member  30  and its peripheral portion  30   a.    
         [0061]    In either case it is possible to detach the upper part of the outer cover portion  38  from the upper portion of the head member  30  by turning up the upper part, separate the outer cover portion  38  from the upper portion of the head member  30  for washing, and elastically and hermetically fit the outer cover portion  38  over the upper portion of the head member  30  again after washing.  
         [0062]    As shown in FIG. 1, the lower part  40  of the outer cover portion  38  is formed with the annular step portion  40   a  circumferentially thereof for easy hermetic contact with the closure member  3 . The annular step portion  40   a  is brought into hermetic pressure-contact with the upper surface (sealing surface)  23   a  of the sealing wall  23 . Besides this sealing portion, a thin lower peripheral edge portion  40   b  that is additionally or optionally formed is brought into hermetic pressure-contact with a sealing surface  23   c  formed on an inner surface of the annular wall of the closure member  3  as shown in FIG. 1.  
         [0063]    The thickness of the lower part  40  may be increased or decreased to meet demands of users related to the flexibility of the material of the outer cover portion  38 , the difference in atmospheric pressure between the reduced-pressure space  24  and the outside, or the like. If the lower part  40  is rigidly formed, it can withstand a larger difference in atmospheric pressure. If the lower part  40  is made flexible, it serves as a safety valve that opens when the difference in atmospheric pressure becomes large. In the case where the desired atmospheric pressure difference is small, it is possible to employ an arrangement such that the upper surface of the closure member  3  is made flat and a lowermost edge of the lower part  40  is brought into pressure-contact with the upper surface of the closure member  3  in a usual condition to provide a sealing effect.  
         [0064]    The seal member  42  shown in FIG. 4 and FIG. 5 is formed into an annular shape having a hollow central portion using an elastic material having a restoring force such as silicone rubber or a heat-resistant synthetic resin having a predetermined elasticity. The seal member  42  has an inner peripheral portion forming a base portion  43  hermetically fitted into a holding groove  21  of the holding member  20  and an outer peripheral portion forming a slightly thicker free edge  44  brought into hermetic pressure-contact with a slightly upwardly inclined flat surface  10  of the step portion  10 . An intermediate portion  45  of the seal member  42  is made thinner so that the seal member  42  is imparted with a sufficient elasticity as a whole. The elasticity of the seal member  42  is such as to allow the free edge  44  to pressure-contact the step portion  10  but not to raise the closure member when the closure member is in a state fitted over the container body. If the air within the container  1  under heating is unusually expanded, the seal member  42  is lifted up to serve as a safety valve.  
         [0065]    Food is put into the food preservative container  1  of the construction described above and the container  1  in the state shown in FIG. 1 is usually stored in a refrigerator. The internal pressure of the container  1  is reduced as the temperature in the container  1  lowers in the refrigerator. Since the peripheral edge of the seal member  42  hermetically pressure-contacts the sealing portion  10  while, at the same time, the sealing portion  40  in the lower part of the outer cover portion  38  hermetically contacts the upper surface of the closure member  3 , there is no communication with outside air and, hence, odors within the container  1  are prevented from transferring to other food stored in the refrigerator.  
         [0066]    When a container is taken out of the refrigerator, the container cannot be opened easily even if the user tries to lift up the closure member  3  because the internal pressure of the container is reduced. As apparent from the foregoing description, the food preservative container of the present invention allows its closure member  3  to be easily lifted up because when the outer cover portion  38  of the finger grip portion, which is formed from the aforementioned flexible material, is gripped with fingers in order to lift up the closure member  3 , the lower part  40  of the outer cover portion  38  of the finger grip portion  16  is partially moved toward the center as shown in FIG. 9 and FIG. 10 and hence slightly detaches from the upper surface of the closure member  3  to release the hermetic pressure-contact with the closure member  3 , thereby allowing air communication between the internal space  11  of the container  1  and the outside through the through-hole  19  or the vent holes  26 .  
         [0067]    When the finger grip portion  16  is to be washed, the finger grip portion  16  is detached from the closure member  3  if the closure member  3  is removed from the container body  2  in the state shown in FIG. 1 and the engagement pawls  35  are gripped with fingers and moved toward the central portion and then drawn out of the through-hole  19  upwardly. The finger grip portion  16  thus detached from the closure member  3  is very easy to wash. Further, when the lower part  40  of the grip outer cover portion  38  circumscribing the finger grip main body  33  is turned up about the upper part  37 , a portion around the engagement portion  34  of the finger grip main body  33  can be easily washed to keep an hygienically favorable state.  
         [0068]    Fitting of the finger grip portion  16  to the closure can be achieved by inserting the engagement portion  34  into the through-hole  19  as shown in FIG. 1. The annular seal member  42  can also become ready for washing if the inner peripheral portion thereof is drawn out of the holding groove  21  that allows fitting and removal of the seal member  42 . The fitting state of the seal member  42  can be restored easily.  
         [0069]    [0069]FIG. 13 through FIG. 18 illustrate embodiments of closure member  3 , finger grip main body  33  attached to the closure member  3  and grip outer cover portion  38  circumscribing the finger grip main body  33 , each having a partially different feature from the corresponding one shown in FIG. 1 through FIG. 12.  
         [0070]    The following description is made with reference to FIG. 13 through FIG. 18. A closure member  3   d  is partially shown only to illustrate the different feature, while many other parts of the closure member  3  having been described with reference to FIG. 1 are omitted together with the illustration of the container.  
         [0071]    The closure member  3   d  has a central portion defining a through-hole  19   b  that is not circular, for example rectangular, in a plan view as shown in FIG. 14(A), and a slightly raised portion  56  around the through-hole  19   b  as shown in FIG. 14(B).  
         [0072]    On an upper side of the closure member  3   d  and about a finger grip main body  33   d  are formed an abutment surface  53 , an introduction groove  54  and a sealing wall  23   d , which circumscribe the finger grip main body  33   d  sequentially. At an innermost location an annular step portion  53  forming the abutment surface  53  is formed continuously with the outer periphery of the slightly raised convex portion  56  to receive an inner free edge  51  of an annular valve member  50 . A trench-like introduction groove  54  is formed next to and continuously with the step portion  53  circumferentially of the step portion  53  as shown in FIG. 14. Further, around the outer periphery of the introduction groove  54  is formed an upright sealing wall  23   d  continuously with and circumferentially around the introduction groove  54  for defining the introduction groove  54 . The sealing wall  23   d  relatively defines the introduction groove  54  and hence may be flush with the upper surface of the closure member  3   d  to define the introduction groove  54  having a greater depth.  
         [0073]    The introduction groove  54  defines a vent hole  26   d  at a single or plural points for providing communication with the inside of the closure member in order for the internal atmospheric pressure of the introduction groove  54  to become equal to the internal atmospheric pressure of the container body  2 .  
         [0074]    An upper portion  52  of the introduction groove  54  on the central side defines an air communication hole  52  at a single or plural points which allows air communication through between a free edge  51  of an annular valve member  50  and the central side of the introduction groove  54  when the free edge  51  of the valve member  50  pressure-contacting the abutment surface  53  is bent and moved toward the bottom of the introduction groove  54  due to a reduction in the internal pressure of the introduction groove  54  (see FIG. 18).  
         [0075]    A convex engagement portion  34   d  formed in a lower portion of the finger grip main body  33   d  of the finger grip portion  16   d  is described below. This engagement portion  34   d  is different from the corresponding one shown in FIG. 1. The engagement portion  34   d  comprises a protruding member  34   b  formed of the same material as a head portion  30   d  of the finger grip main body and protruding downwardly from the lower side of the head portion  30   d , and an engagement pawl  35   d  which is shaped corresponding to the through-hole  19   b  shaped non-circular in the plan view and defined in the closure member  3   d  and is sized slightly smaller than the through-hole  19   b  for insertion into and withdrawal from the through-hole  19   b . The engagement pawl  35   d  has a free end configured to disengageably engage a lower edge  19   e  of a side of a smaller-diameter  19   c  of the through-hole  19   b  as shown in FIG. 13(A) by rotating the free end. The engagement pawl  35   d  is shaped non-circular, for example, rectangular in the back view.  
         [0076]    Grip outer cover portion  38   d  is formed from a flexible and airtight material as is the grip outer cover portion shown in FIG. 1.  
         [0077]    An upper part  39 d of the outer cover portion  38   d  is joined with the finger grip main body  33   d  as shown in the drawings. An annular inner member  39   ad  at the upper part of the outer cover portion  38   d  is joined with the underside of a peripheral portion  30   ad  of the head member. In a fitting state shown in FIG. 13(A) the annular inner member  39   ad  is compressed between the upper and lower members, so that communication between outside air and a reduced-pressure space  24   bd  is cut off. A lower part  40   d  of the outer cover portion  38   d  is capable of being turned up about an upper portion  39   d  as shown in FIG. 12.  
         [0078]    The lower part  40   d  of the outer cover portion  38   d  annularly extends so as to hermetically pressure-contact an upper portion of the upright sealing wall  23   d  of the closure member  3   d . In this state the reduced-pressure space  24   bd  is hermetically cut off against outside air as shown in FIG. 1.  
         [0079]    The annular valve member  50  formed from the same material as the lower part  40   d  of the outer cover portion  38   d  extends from the inner side of the lower part  40   d  toward the annular abutment surface  53  over the trench-like introduction groove  54  as shown in FIG. 13(A).  
         [0080]    The free edge  51  of the valve member  50  hermetically pressure-contacts the annular abutment surface  53  to cut off air communication between a second reduced-pressure space  24   bd  defined inside the outer cover portion  38   d  and a reduced-pressure space  24   d  defined under the annular valve member  50  on the container body side.  
         [0081]    The outer cover portion  38   d  is formed from a flexible and elastic material so that when the outer cover portion  38   d  is gripped with fingers to lift up the closure member  3   d  (see FIG. 17), the lower part  40   d  of the outer cover portion  38   d  is partially moved toward the center and hence detaches from the sealing wall  23   d  of the closure member  3   d  to release the hermetic state of the reduced-pressure space  24   d  against outside air thereby allowing air communication between an internal space  11   d  of the container  1  and the outside through a vent hole  26   d.    
         [0082]    [0082]FIG. 18 shows an embodiment of outer cover portion  38   d  having an outer periphery defining an optional air introduction hole  55 . This embodiment is constructed so that the second reduced-pressure space  24   bd  is allowed to previously communicate with outside air in the state shown in FIG. 13(A). The provision of the air introduction hole  55  enables the container to exhibit a special function. When the container body  2  fitted with the closure member  3  is stored in a refrigerator, the finger grip portion  16   d  initially assumes the state shown in FIG. 13(A). As the inside of the container is cooled to reduce the internal pressure of the container, a negative pressure is provided in the reduced-pressure space  24   d  and, hence, the annular valve member  50  strongly contacts the sealing wall  23   d  and the abutment surface  35  thereby cutting off air communication therethrough and closing the upper portion of the air communication hole  52 .  
         [0083]    As the negative pressure in the reduced-pressure space  24   d  further grows, the entire container receives increasing pressure on its periphery. Under such a condition, the annular valve member  50  having elasticity, if previously formed slightly thinner, is drawn downwardly as shown in FIG. 18 and hence elastically bent and slightly moved laterally to open the upper portion of one air communication hole  52  thereby permitting outside air to naturally flow thereinto from the second reduced-pressure space  24   bd . By adjusting the reduced-pressure condition of the inside of the container in this way, it is possible to prevent the container from being crushed or partially damaged by external pressure. When the internal pressure of the container comes close to the atmospheric pressure again, the annular valve member  50  having a restoring force restores its state shown in FIG. 13 and keeps its hermetic sealing state.  
         [0084]    It should be noted that parts shown in FIG. 13 through FIG. 18 that are considered identical with or equivalent to corresponding parts shown in FIG. 1 through FIG. 12 in function, property, feature or the like are designated by like reference characters added with “d” for the purpose of avoiding repetition of description.  
         [0085]    As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific embodiments thereof except as defined in the appended claims.