Patent Publication Number: US-2021163211-A1

Title: Thermally insulated container

Description:
TECHNICAL FIELD 
     The present invention relates to a thermally insulated container having a multiple wall structure. 
     BACKGROUND ART 
     The following thermally insulated containers are being practically used, e.g., as mugs: thermally insulated containers having a multiple wall structure including inner and outer container parts defining therebetween a sealed space having a predetermined size so as to keep its contents at an elevated or reduced temperature. A method for manufacturing such a thermally insulated container is disclosed e.g., in the below-identified Patent Document 1. In this method, while keeping a predetermined gap between an externally mounted molded member (corresponding to the outer container part) and an internally mounted molded member (corresponding to the inner container part), the diameter of an open end portion of the externally mounted molded member is reduced until the open end portion of the outer molded portion is brought into close contact (pressure contact) with an open end portion of the internally mounted molded member, thereby forming a joint portion at which the molded members are joined together. Air may be left in the gap between the inner and outer molded members, or this gap may be in a vacuum state. (See, e.g., paragraphs 0019 to 0020 and FIG. 3 of Patent Document 1.) 
     The inner and outer container parts can be fixedly joined together by closely pressing them against each other as disclosed in Patent Document 1, or can be integrally joined together by metal welding if the container parts are made of metal, or by plastic welding if the container parts are made of resin. 
     PRIOR ART DOCUMENT(S) 
     Patent Document(s) 
     Patent document 1: Japanese Unexamined Patent Application Publication No. 2008-221317 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     In order to fixedly/integrally join the inner and outer container parts by pressing them against each other as disclosed in Patent Document 1, or by metal welding, plastic welding, etc., an elaborate device and/or a skilled metal welder is needed, which increases the manufacturing cost or makes mass-production difficult. Also, if the inner and outer container parts are integrally joined together by metal welding, since the same metal is preferably used for the inner and outer container parts, variations of metals selectable for the inner and outer container parts are limited. 
     A thermally insulated container having such a multiple wall structure can be heated directly if it has a vacuum interior structure, but cannot be heated directly if air is present in the container, because such direct heating will expand the air. However, a user may not be able to determine whether or not the thermally insulated container has a vacuum interior structure, and, in this case, the user may have trouble when heating the container. 
     It is an object of the present invention to provide a thermally insulated container having a multiple wall structure which can be constructed in a simple manner, and which is capable of keeping its contents at an elevated or reduced temperature. 
     Means for Solving the Problems 
     In order to achieve the above object, the present invention provides a thermally insulated container comprising: a tubular inner container part having a closed bottom and an open top end; a tubular outer container part having a closed bottom and an open top end, wherein the tubular inner container part is received in the tubular outer container part; and a connection member, wherein, with the tubular inner container part received in the tubular outer container part, the connection member is disposed between an upper end portion of the tubular inner container part and an upper end portion of the tubular outer container part so as to define a sealed space having a predetermined size between an outer peripheral surface of the tubular inner container part and an inner peripheral surface of the tubular outer container part.  
     By connecting the inner and outer container parts together through the connection member, it is possible to omit welding or a similar time-consuming step, and thus to reduce the manufacturing cost of a thermally insulated container having a multiple wall structure and capable of keeping its contents at an elevated or reduced temperature. Also, by removing the inner container part from the outer container part, it is possible to conveniently heat only the inner container part. It is also possible to separately use the inner container part and the outer container part as independent containers, instead of using the entire container as a double-walled thermally insulated container. For example, two users can separately use the inner container part and the outer container part, or a single user can put a food into the inner container part, and a beverage into the outer container part. 
     In the thermally insulated container, it is preferable that the tubular inner container part has an outer periphery including a tapered surface of which an outer diameter decreases toward a bottom end of the tubular inner container part, and that the connection member has an inner periphery including a tapered surface of which an inner diameter decreases in an axial direction of the connection member such that the tapered surface of the connection member is disposed along the tapered surface of the tubular inner container part. 
     By forming such tapered surfaces on both of the inner container part and the connection members, when the inner container part is inserted through the connection member with the connection member fitted to the upper end portion of the outer container part, the inner container part is smoothly guided by the connection member so as to become coaxial with the outer container part. As a result, a circumferential gap having a uniform size is defined between the inner peripheral surface of the outer container part and the outer peripheral surface of the inner container part, thereby providing an improved ability to keep the contents at an elevated or reduced temperature. Also, when the inner container part is inserted, the tapered surfaces of the inner container part and the connection member come into surface contact with each other, thereby preventing the inner container part from being further inserted. As a result, a gap having a predetermined size is defined between the bottom surfaces of the inner container part and the outer container part. Since the bottom surfaces of the inner and outer container parts are kept out of contact with each other, the contents of the container can be reliably kept at an elevated or reduced temperature. 
     In the thermally insulated container having such a tapered surface on its inner container part, the connection member preferably includes: a plurality of radially inwardly rising protrusions on a radially inner surface of an upper end portion of the connection member; and a plurality of radially inwardly rising protrusions on a radially inner surface of a lower end portion of the connection member. 
     By forming such protrusions, at the initial stage of the insertion of the inner container part into the outer container part, it is possible to reduce the friction between the connection member and the lower end portion (small diameter portion) of the inner container part due to their contact with each other, and thus to smoothly insert the inner container part into the outer container part. Also, upon completion of the insertion, the upper end portion (large diameter portion) of the inner container part strongly abuts against the protrusions on the upper end portion of the connection member, so that the inner container part is reliably retained by the connection member (and thus by the outer container part). The positions and the number of the protrusions on each of the upper and lower end portions of the connection member are not particularly limited, but preferably, such protrusions are disposed at regular intervals in the circumferential direction. For example, such protrusions may be composed of three protrusions disposed at 120-degree intervals, or four protrusions disposed at 90-degree intervals. 
     In the thermally insulated container, the connection member is preferably an injection-molded member. 
     The injection-molded connection member has a predetermined rigidity, and thus is less likely to deform when the inner container part is inserted into the connection member. This prevents the inner container part from being inserted into the outer container part while being tilted relative to the outer container part, which in turn prevents the gap between the inner and outer container parts from partially becoming narrow, or prevents the inner and outer container parts from partially coming into contact with each other, thereby maintaining heat-insulating properties of the container. 
     In the thermally insulated container, a material forming the tubular inner container part may be different in kind from a material forming the tubular outer container part. 
     In other words, according to the intended use, it is possible to select an optimal combination of materials for the inner and outer container parts. For example, the inner container part, for which heat resistance is required, may be made of stainless steel, whereas the outer container part may be made of a resin material, or titanium, aluminum or an alloy thereof so as to be light in weight. 
     In the thermally insulated container, one of a cooling medium and a heating medium may be placed in the sealed space. 
     By placing a heating or cooling medium in the sealed space, not only is it possible to simply maintain the temperature of the contents of the container such as a beverage, but the contents can also be positively heated or cooled. For example, it is possible to make ice cream, or cook food, in the inner container part. The hearing or cooling medium may be, e.g., refrigerant, ice water or hot water. 
     Effects of the Invention 
     Since the multiple wall structure of the thermally insulated container according to the present invention is constructed by the inner container part, the outer container part, and the connection member disposed between the inner and outer container parts, this thermally insulated container can be manufactured at a low cost, and still shows sufficient ability to keep its contents at an elevated or reduced temperature, compared to a thermally insulated container of which the inner and outer container parts are integrally joined together by e.g., welding. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a plan view of a thermally insulated container (mug) according to a first embodiment of the present invention. 
         FIG. 1B  is a side view of the thermally insulated container (mug) according to the first embodiment. 
         FIG. 2  is a sectional view taken along line II-II of  FIG. 1B . 
         FIG. 3  is an enlarged sectional view of a portion of  FIG. 2 . 
         FIG. 4  is a perspective view of the thermally insulated container of  FIGS. 1A and 1B . 
         FIG. 5  is an exploded side view of the thermally insulated container of  FIGS. 1A and 1B . 
         FIG. 6  is a perspective view of the thermally insulated container of  FIGS. 1A and 1B . 
         FIG. 7  is a sectional view of a thermally insulated container according to a second embodiment of the present invention. 
         FIG. 8  is a sectional view of a thermally insulated container according to a third embodiment of the present invention. 
         FIG. 9  is a sectional view of a thermally insulated container according to a fourth embodiment of the present invention. 
         FIG. 10  is a sectional view of a thermally insulated container according to a fifth embodiment of the present invention. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
       FIGS. 1A to 6  illustrate a thermally insulated container  10  according to the first embodiment of the present invention. The thermally insulated container  10  is a mug (the mug is also hereinafter denoted by numeral “ 10 ”) having a double wall structure, and mainly used outdoors or at home. The mug  10  includes, as its main elements, an inner container part  11 , an outer container part  12 , and a connection member  13 . 
     The inner container part  11  is a tubular member having a closed bottom and an open top end, for holding beverages and other items. The inner container part  11  has an outer periphery including, at its portion close to the top end, a tapered surface  14  of which the outer diameter decreases toward the bottom end of the inner container part  11 . In the embodiment, the inner container part  11  is made of stainless steel, but it may be made of a resin material if high strength or heat resistance is not required. 
     The mug  10  may include a lid  15  disposed at the top end opening of the inner container part  11 . The lid  15  is formed with a drinking opening  16  and an air hole  17  so that, when a beverage flows out of the inner container part  11  through the drinking opening  16 , air simultaneously flows into the inner container part  11  through the air hole  17 , thereby enabling the beverage to flow out smoothly. A seal member  18  is disposed at the outer peripheral edge of the lid  15  so as to reliably keep the lid  15  fitted in the inner container part  11 . 
     The thermally insulated container  10  of the embodiment is exemplified as a mug  10  of which the lid  15  has a drinking opening  16  and an air hole  17  so that a user can drink the beverage in the inner container part  11  with the lid  15  attached. However, the drinking opening  16  and the air hole  17  may be omitted to provide heat insulating and sealing properties to the lid  15 . The thermally insulated container  10  including such a lid  15  can be used not only as a mug  10 , but as e.g., a pot or a jar. 
     The outer container part  12  is a tubular member having a closed bottom and an open top end, in which the inner container part  11  is received. The outer container part  12  has a uniform outer diameter from its top end to its bottom end. In the embodiment, the outer container part  12  is made of the same material as the inner container part  11 , i.e., stainless steel, but it may be made of a resin material so that heat is not transferred from the mug  10  to a user&#39;s hand gripping the mug  10 . Also, if lightness in weight is important, the outer container part  12  may be made of titanium, aluminum, or an alloy thereof. 
     The inner diameter of the outer container part  12  at its open end is equal to the inner diameter of the inner container part  11  at its open end (see  FIG. 3 ). Therefore, instead of putting the lid  15  on the inner container part  11 , the lid  15  can be put on the top end opening of the outer container part  12 , too. 
     With the inner container part  11  received in the outer container part  12 , the connection member  13  defines a sealed space having a predetermined size between the outer peripheral surface of the inner container part  11  and the inner peripheral surface of the outer container part  12 . For this purpose, the connection member  13  is disposed between the upper end portions of the inner and outer container parts  11  and  12 . The connection member  13  has, on its inner periphery, a tapered surface  19  of which the inner diameter decreases axially downwardly of the connection member  13 . The tapered surface  19  is disposed along the tapered surface  14  of the inner container part  11 . The lower end portion of the connection member  13  that is located below the tapered surface  19  has a smaller diameter than the upper end portion of the connection member  13  that is located above the tapered surface  19 . The connection member  13  is formed by injection molding of a resin material, and is rigid enough not to be deformed to a large degree when the inner container part  11  is inserted into the outer container part  12 . 
     The connection member  13  includes a plurality of radially inwardly rising protrusions  20  on the radially inner surface of its upper end portion; and a plurality of radially inwardly rising protrusions  21  on the radially inner surface of its lower end portion (see  FIG. 6 ). The protrusions  20  and  21  are ribs extending in the axial direction of the connection member  13 . In the embodiment, the protrusions  20 ,  21  on each of the upper and lower end portions of the connection members  13  are exemplified as three protrusions circumferentially disposed at intervals of 120 degrees, but the positions and the number of the protrusions  20 ,  21  are not particularly limited, and may be altered as necessary. 
     A seal member  22  is disposed at the radially outer surface of the lower end portion of the connection member  13 . The seal member  22  is made of silicon resin, and reliably keeps the connection member  13  fitted in the outer container part  12  even if the connection member  13  is a rigid injection-molded member. While, in the embodiment, the connection member  13  and the seal member  22  are separate members, they may be formed integrally with each other using a relatively soft material such as silicon resin. 
     The connection member  13  partially covers the upper end portion of the inner container part  11  (see  FIG. 2 ), thus reducing the contact area of a user&#39;s lips with the upper end portion of the inner container part  11 . This minimizes the sensation of heat felt when the user&#39;s lips touch the inner container part  11  with a high-temperature beverage in the mug  10  (i.e., in the inner container part  11 . 
     It is now described how the mug  10  is assembled. First, as illustrated in  FIG. 6 , the connection member  13  is fitted into the top end opening of the outer container part  12 . Then, the inner container part  11  is inserted through the connection member  13  and into the outer container part  12  so as to be arranged coaxially with the outer container part  12 . At the initial stage of the insertion, the protrusions  21  of the connection member  13  on the radially inner surface of its lower end portion come into contact with the lower end portion (small diameter portion) of the inner container part  11 . Since the protrusions  21  come into substantially line contact with the lower end portion of the inner container part  11 , and are shaped so as to guide the insertion of the lower end portion of the inner container part  11 , it is possible to minimize the friction between the inner container part  11  and the connection member  13 , and thus to smoothly insert the inner container part  11 . 
     Also, even if the inner container part  11  and the outer container part  12  are not coaxial with each other at the initial stage of the insertion, the inner container part  11  eventually becomes coaxial with the outer container part  12  due to the tapered surface  14  of the inner container part  11  coming into surface contact with the tapered surface  19  of the connection member  13 . 
     Also, upon completion of the insertion, the protrusions  20  of the connection member  13  on the radially inner surface of its upper end portion strongly abut against the upper end portion (large diameter portion) of the inner container part  11 , so that the inner container part  11  is reliably retained by the connection member  13  (and thus by the outer container part  12 ). This reliably prevents the separation of the inner container part  11  when the mug  10  is tilted. 
     As necessary, a heating or cooling medium such as refrigerant, ice water or hot water may be placed in the sealed space between the inner container part  11  and the outer container part  12  so that the contents of the mug  10  can be not only simply kept at an elevated or reduced temperature, but also positively heated or cooled. 
       FIG. 7  illustrates a mug  10  according to the second embodiment of the present invention. The mug  10  of the second embodiment is identical in basic structure to the mug  10  of the first embodiment, but the shapes of the inner container part  11 , outer container part  12  and connection member  13  are different. 
     Specifically, the mug  10  of the second embodiment has, besides the tapered surface on the inner container part  11 , an additional tapered surface on the outer container part  12 , and thus the outer shape of the mug  10  is such that its lower end portion is slimmer than its upper end portion. Also, two seal members  22  are disposed on the outer periphery of the connection member  13  so as to be vertically spaced apart from each other, thereby ensuring airtightness between the outer container part  12  and the connection member  13 . An externally mounted member  23  is disposed on the outer peripheral surface of an upper end portion of the outer container part  12 . The externally mounted member  23  is provided to enable a user to grip the mug  10  more reliably (easily). 
       FIG. 8  illustrates a mug  10  according to the third embodiment of the present invention. The mug  10  of the third embodiment is identical in basic structure to the mug  10  of the first embodiment, but the shape of the connection member  13  is different. 
     Specifically, the connection member  13  of the mug  10  according to the third embodiment has no seal member  22 , and is wedged between the inner and outer container parts  11  and  12  by the force with which the inner container part  11  is fitted into the outer container part  12 . In this arrangement, since the shape of the connection member  13  can be simplified, it may be possible to reduce the manufacturing cost. The connection member  13  of this embodiment is preferably made of silicon resin, a material having flexibility. An externally mounted member  23  is disposed on the outer peripheral surface of the upper end portion of the outer container part  12 . The externally mounted member enables a user to grip the mug  10  more reliably (easily). 
       FIG. 9  illustrates a mug  10  according to the fourth embodiment of the present invention. The mug  10  of the fourth embodiment is identical in basic structure to the mug  10  of the first embodiment, but the shapes of the inner container part  11 , outer container part  12  and connection member  13  are different. 
     Specifically, the inner container part  11  of the mug  10  according to the fourth embodiment has a tapered surface  14  near its top end, and has an outer diameter that gradually decreases from the tapered surface  14  to the bottom end of the inner container part  11 . The outer container part  12  has an outer diameter that gradually decreases from a portion of the outer container part  12  close to its top end to its bottom end. Therefore, the outer shape of the mug  10  is such that its lower end portion is slimmer than its upper end portion. The connection member  13  has no seal member  22 , and is wedged between the inner and outer container parts  11  and  12  by the force with which the inner container part  11  is fitted into the outer container part  12 . In this arrangement, since the shape of the connection member  13  can be simplified, it may be possible to reduce the manufacturing cost, as in the third embodiment. 
       FIG. 10  illustrates a mug  10  according to the fifth embodiment of the present invention. The mug  10  of the fifth embodiment is identical in basic structure to the mug  10  of the first embodiment, but the shapes of the inner container part  11 , outer container part  12  and connection member  13  are different. 
     Specifically, the inner and outer container parts  11  and  12  of the mug  10  according to the fifth embodiment are identical in shape to each other, and each has an outer diameter that gradually decreases from a portion of the container part close to its top end to its bottom end. The connection member  13  has no seal member  22 , and is wedged between the inner and outer container parts  11  and  12  by the force with which the inner container part  11  is fitted into the outer container part  12 . In this arrangement, since the inner and outer container parts  11  and  12  can be formed with the same mold, and the shape of the connection member  13  can be simplified, it may be possible to reduce the manufacturing cost. 
     The above embodiments are mere examples in every respect. For example, the shapes of the elements of the mug  10 , such as the inner container part  11 , the outer container part  12  and the connection member  13 , may be altered as necessary, provided that the object of the present invention, i.e., to provide a thermally insulated container having a multiple wall structure which can be constructed in an simple manner, and which is capable of keeping its contents at an elevated or reduced temperature, can be achieved. 
     For example, while the mug  10  is exemplified as having a double wall structure in each of the above embodiments, the mug  10  may have a triple or more wall structure. Such a mug  10  may show an improved ability to keep its contents at an elevated or reduced temperature.  
     While the mug  10  having a double wall structure described in each of the above embodiments is capable of keeping its contents at an elevated or reduced temperature, a portion of the outer container part  12  or the connection member  13  of the mug  10  may have the function of a simplified valve element or air pump capable of discharging air in the space between the two walls of the mug (thereby creating a vacuum or a decompressed state in this space). This further improves the ability of the mug  10  to keep its contents at an elevated or reduced temperature, compared to when there is an air layer at atmospheric pressure in the space between the two walls of the mug  10 . 
     DESCRIPTION OF REFERENCE NUMERALS 
       10 : thermally insulated container (mug) 
       11 : inner container part 
       12 : outer container part 
       13 : connection member 
       14 : tapered surface (of the inner container part) 
       15 : lid 
       16 : drinking opening 
       17 : air hole 
       18 : seal member (for the lid) 
       19 : tapered surface (of the connection member) 
       20 : protrusion (on the upper end portion of the connection member) 
       21 : protrusion (on the lower end portion of the connection member) 
       22 : seal member (for the connection member) 
       23 : externally mounted member