Abstract:
An easily closable and openable container system includes a number of features which facilitate easy opening and closing while maintaining a high seal. In a first embodiment, the opening forces can be concentrated on one narrow side which includes a lip on one side of a lid flange and with an angled portion on the opposite side of the flange to give ease of opening with less force involved. In a second embodiment where one side is not significantly shorter than a longest side, the lid flange is located at a corner to concentrate the leverage for opening. A continuous flange surrounds a generally planar member and mates with a outwardly projecting rim. The flange includes a pair of surfaces, including an inwardly angled surface which acts to form a stable seal, and actually urges the lid downward as the natural sealing force from the flange is applied.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a number of advantageous structures and devices for safe, convenient, easy to open and close containment sealing systems which are ideal for preserved sealing, particularly for foodstuffs. 
       BACKGROUND OF THE INVENTION 
       [0002]    Sealed containers are typically used in conjunction with food and other materials to be protected from moisture and the environment, or used with liquids and are to be isolated from spillage. Most sealed containers commercially available have compromised the sealing engagement in order to facilitate a snap shut closure. Quick engagement structures don&#39;t typically produce as strong of a seal as a more extended seal with significant sealing forces. Conversely, a good seal typically involves a complex locking arrangement or an extended seal. However, most complex locking arrangements or extended high pressure seals are inconsistent with ease of use and low expense. 
         [0003]    The need for an efficient and easily operable seal is especially needed with respect to food containers which may be subjected to microwave use. The failure to form a lid hugging seal can cause containers holding the heated food to explode in the microwave causing damage and a mess. The instant container includes a superior seal as well as a pressure relief valve to that it can be employed to maximum effect in a microwave to insure that the lid stays on. If the pressure exceeds the pressure rating of the safety/pop valve assembly, which will typically be far less than the pressure necessary to dislodge the sealed lid, the safety/pop valve assembly will open to enable gaseous pressure to subside. 
       SUMMARY OF THE INVENTION 
       [0004]    An easily closable and openable container system includes a number of features which facilitate easy opening and closing while maintaining a high seal. In a first embodiment, the opening forces can be concentrated on one narrow side which includes a lip  41  on one side of a lid flange and with an angled portion on the opposite side of the flange to give ease of opening with less force involved. In a second embodiment where one side is not significantly shorter than a longest side, the lid flange is located at a corner to concentrate the leverage for opening. 
         [0005]    A continuous flange surrounds a generally planar member and mates with a outwardly projecting rim. The flange includes a pair of surfaces, including an inwardly angled surface which acts to form a stable seal, and actually urges the lid downward as the natural sealing force from the flange is applied. A second surface, below the inwardly angled surface, is the first beveled surface which has sufficient angle to enable the upper part of the upper wall to engage and be urged into position with respect to the inwardly angled surface, and without the user having to provide stretching or two handed operation. In essence, the second surface is beveled to engage the upper wall and enable a mechanically advantaged force to fit the flange over the upper rim of the upper wall so that the sealing surfaces can be brought stably together with simple downward pressure. 
         [0006]    The lateral sectional details of the flange portion include a number of angular relationships which contribute to the ease of use and positivity of sealing of the containers illustrated. A differential width flange can also provide additional ease of manipulation at a preferred point of opening. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The invention, its configuration, construction, and operation will be best further described in the following detailed description, taken in conjunction with the accompanying drawings in which: 
           [0008]      FIG. 1  illustrates a perspective view of a rectangular container with a lid in place and illustrating the extended lip, pop valve and top configuration; 
           [0009]      FIG. 2  is a sectional view taken along line  2 - 2  of  FIG. 1  and illustrates further details of the lid, flange portion, lip, pop valve and top configuration; 
           [0010]      FIG. 3  is an expanded view of the left side of the cross sectional figure illustrated in  FIG. 2  and taken about line  2 - 2  of  FIG. 2 ; 
           [0011]      FIG. 4  illustrates a perspective view of a square container with a lid in place and illustrating the corner located extended lips, pop valve and top configuration; 
           [0012]      FIG. 5  is a sectional view taken along line  5 - 5  of  FIG. 4  and illustrates further details of the lid, flange portion, lip, pop valve and top configuration; 
           [0013]      FIG. 6  is an expanded view of the left side of the cross sectional figure illustrated in  FIG. 5  and taken about line  6 - 6  of  FIG. 5 ; and 
           [0014]      FIG. 6  illustrates a round container which uses an acentric or non-constant cross section flange portion to facilitate opening. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0015]    The description, construction and operation of the sealing system of the invention will be best illustrated by beginning with reference to  FIG. 1 , which illustrates a perspective view of a rectangular oblong container  21  including a lid  23  and a base container  25 . The base container  25  may include a generally circumferentially outwardly projecting rim  27  which may serve as a reinforcement for the upper part of the base container  25  and as a visual indicator that the lid  23  is fitted in place, by visually exacerbating any displacement from a flat sealed condition. Also seen are a periodic series of vertical reinforcements  29  which project slightly outwardly from the generally vertical extent of the base container  25 . 
         [0016]    The lid  23  has a number of features. Lid  23  includes a flange portion  31  made of a more flexible material. Flange portion  31  is continuous adjacent the periphery of the lid  23 . Into the flange portion  31 , a harder plastic portion  33  is fitted and sealed. Sealing may be by ultrasonic welding, fusion, melting, or molecular bonding to name but a few of the methods of permanent joining, especially of a softer material flange portion  31  to the harder plastic portion  33 . The harder plastic portion  33  has surface features including a more sharply downwardly angled transition  35  on three sides leading to a generally flat floor  37 . At one end of the lid  23 , the transition from the flange  31  to the floor  37  is through an angled portion  39 . At the end of the lid  23  most closely adjacent the angled portion  39 , a lip  41  extends away from a shorter width side of the lid  23 . The lip  41  is typically integrally formed with the flange  31  and is therefore made of softer material. 
         [0017]    At the center of the generally flat floor  37  is a safety/pop valve assembly  45 . The assembly includes a finger well  47  adjacent a flexible member  49  which is mounted into the a portion of the floor  37 . The finger well facilitates manual engagement and lifting of the flexible member  49 . The flexible member  49  may fit within a flush space so that the top of the floor  37  will have an even, flat profile. In one embodiment, the flexible member may be “spear locked” through a first aperture in the floor  37  at one end of the flexible member  49 . The floor  37  may include a second aperture sized to accept a peg shaped projection from the flexible member such that pressure within the container  21  of a pre-determined magnitude can cause the flexible member to “pop” open upon achievement of a pre-determined internal pressure, to allow pressurized gasses to escape from within the container. This is typically the case where the container of food is used in a microwave, and the pressure setting is pre determined based upon the open area of the aperture. The triggering of the pressure relief valve is by expelling the peg shaped projection (not shown in FIG.  1 ) and causing the flexible member  49  to bend upwardly. Typically the projection does not re-enter the aperture and additional water vapor or air is permitted to continue to escape. In the alternative, the user can open the safety/pop valve assembly  45  manually in advance of heating, to deliberately allow vapor to escape. 
         [0018]    Referring to  FIG. 2 , a section taken along line  2 - 2  of  FIG. 1  illustrates further details of the internals of the container  21 . Beginning at the right side of the figure, the lip  41  has an underside surface which extends to a pair of peripherally inwardly directed surfaces including a first beveled surface  53  which leads to an inwardly angled surface  55  which lies adjacent a rim capture underside surface  57 . The other side of the rim capture underside surface  57  is bounded by a downwardly directed rim  59 . 
         [0019]    The lid  23  is shown in place fitted atop the base container  25 , but the drawing shows overlap between portions of the first beveled surface  53 , inwardly angled surface  55 , and an upper wall  61  of the base container  25  above the outwardly projecting rim  27 . Upper wall  61  is continuous about the base container  25 . This rendering illustrates the degree to which the downward extending portion of the flange portion  31  would extend inwardly if it were not urged outwardly by the upper wall  61 . In response to being urged outwardly by the upper wall  61 , the downward extending portion of the flange portion  31  exerts sealing pressure on the outside of the upper wall  61 . 
         [0020]    Note also that the wall  61  is angled outwardly with respect to a floor  63 . The wall  61  is shown as generally linear before a curved transition into floor  63 , but the wall  61  may be angled only at the uppermost portion, such as above rim  27 . 
         [0021]    Referring again to the horizontal portion of the flange portion  31 , a channel  65  is seen engaging the outer edge of the harder plastic portion  33  of the lid  23 . In this configuration, the channel  65  provides three bonding surfaces to the outside edge of the harder plastic portion  33  of the lid  23 , including part of an upper surface, an end edge surface and part of a lower surface. In other words, the outside of the harder plastic portion  33  fits within and is bonded into the channel  65 . 
         [0022]    Also seen is a slight, thickening of the wall  61  just above the outwardly projecting rim  27 , with a slight angled portion  69 . As can be seen from the structures described thus far for  FIG. 2 , two structural accommodations are combined in order to enable container  21  to be more easily opened. The provision of an angled portion  39  adjacent the outwardly extending lip  41  enables mechanical advantage to be more easily applied to left off the lid  23  at the more narrow end of the lid  23 . First, locating the lip  41  at the narrower portion adds to the focussing of opening energy applied at the lip  41 . If the lip  41  were at the wider side of the lid  23 , the opening force would be spread along a wider length of material and the material would simply twistably absorb the force to require a greater force to be applied to open the container  21 . 
         [0023]    The provision of the angled portion  39  provides a longer flexure distance and provides a natural table for downward pressure. Without the angled portion  39 , any lifting of the lip  41  would involve a more severe bending moment between the flange portion  31  and the portion of the generally flat floor  37  which would otherwise be immediately adjacent the flange portion  31  which would be present in the absence of angled portion  39 . The more gently angled portion  39  thus acts to spread and facilitate the flexure along the length of the lid  23 , while at the same time providing a higher surface for giving the hand greater leverage with respect to the lip  41 . Without the angled portion  39 , the user&#39;s hand would tend to curl around the flange portion  31  adjacent the lip  41 . Where hot material is within the container  21 , the curling of the user&#39;s hand around the flange portion  31  increases the chance of burns. The provision of the angled portion  39  enables a stable raised portion which helps the user open the lid  23  with the hand held farther away from the container  21 . 
         [0024]    Further to the left of the angled portion  39 , the finger well  47  is seen. The flexible member  49  can be seen as projecting slightly over the deepest part of the finger well  47 . Also can be seen are two projections extending downwardly from the flexible member  49 . Farthest from the end overlying the finger well  47 , a solid plug  73  sealingly fits through an aperture  75  to solidly and sealingly hold the area of the flexible member  49  immediately surrounding it. Spaced apart from the solid plug  73  and aperture  75  is a vent aperture  77  into which fits an annular cylindrical projection  79 . Knowing the materials, tolerances of the vent aperture  77  and annular cylindrical projection  79 , as well as the diameter of a vent aperture  77  and annular cylindrical projection  79 , the internal pressure within the container  21  which will cause the annular cylindrical projection  79  to be forced through the vent aperture  77  can be easily known. Then, the sizes of the vent aperture  77  and annular cylindrical projection  79  which seals into the vent aperture  77  can be selected to cause the flexible member  49  to open upon the achievement of a predetermined pressure within the container  21 . 
         [0025]    Referring to the far left side of  FIG. 2 , as well as referring for the first time to  FIG. 3 , an expanded view of the relationships taken along section line  3 - 3  of  FIG. 2  illustrates the further details of the interaction between the flange portion  31  and the upper wall  61  of the base container  25 . As was mentioned earlier, there is some overlap seen as the angles and positions of the component parts are in the non-stressed position. The main movements of the component parts seen will be largely an angular displacement of the downward portion of the flange portion  31  of about six degrees. 
         [0026]    The expanded  FIG. 3  also facilitates a discussion of dimensioning as might be appropriate for a small container of from about 15 to 30 centimeters long. The wall  61  of the base container  25  below the outwardly projecting rim  27  may be about two millimeters while the thickness of the wall  61  above the outwardly projecting rim  27  may be about one and a half millimeters. This provides some complementary flexibility to the wall  61  above the outwardly projecting rim  27  so that the angular displacement can be somewhat shared (slightly) with the downwardly extending portion of the flange. 
         [0027]    Other dimensions which may preferably be employed include what can now be clearly seen as a vertical or downward web  81  of the flange portion  31  which may have a length of about thirteen and a half centimeters below a above a top or horizontal web  83  of flange portion  31 . The width of the horizontal web  83  may be about nine centimeters with the depth of the channel  65  being about two centimeters. As can also be seen, the harder plastic portion  33  has a reduced thickness portion where it enters the channel  65 . The main thickness of the harder plastic portion  33  is about two and a third centimeters, but the thickness is reduced at the point of entry to the channel  65  to about one and a third centimeters. 
         [0028]    Both the angularity and the provision of angled surfaces contribute to the ease of use of the container  21 . The general downward extent of the vertical web  81  with respect to the horizontal web  83  may preferably have an angle α of from about ninety degrees to about ninety six degrees and preferably about ninety three degrees. The general outward angled nature of the flange vertical web  83  may help to contribute to both ease of attachment of the lid  23  to the base container  25 , as well as to help the user grasp the underside of vertical web  83  especially where the lid  23  is partially off of the base container  25 . 
         [0029]    Two other angles seen to the inside of the flange  31  include an angle β that the inwardly angled surface  55  makes with respect to the horizontal web  83 , and is about eighty degrees. Put another way, the inwardly angled surface  55  forms an inward ramp having an angle of from about fifteen to about five degrees and preferably about ten degrees from a vertical taken with respect to the horizontal web  83 . Since the outside of the vertical web  81  is angled about three degrees away from straight vertical, the inwardly angled surface  55  has an angle of about thirteen degrees taken with respect to the outside of the vertical web  81 . 
         [0030]    In the Figure, the inwardly angled surface  55  is shown as crossing into, or invading the area occupied by the upper wall  61  when in fact the vertical web  81  would normally be expected to bend outwardly to accommodate the upper wall  61 . An angle γ, is taken between the horizontal web  83  (which is not expected to deflect significantly when the lid  23  is fitted onto the base container  25 ) and the center of the upper wall  61 , but taken with respect to the outer surface of upper wall  61  and which may be from about eighty four to about eighty eight degrees but may be more preferably about eighty six degrees. Thus, the upper wall is tilted outward with respect to the vertical of from about two to about six degrees and may be tilted preferably about four degrees. Also, the inwardly angled surface  55  is inwardly angled by about six degrees more than the upper wall  61  would seem to allow and thus with respect to the vertical is inwardly angled by about ten degrees. It is the force created when the horizontal web  81  is flexed outwardly which is brought to bear on the outside of wall  61 . Further, this sealing occurs over a height of the outside of the upper wall of about six centimeters. As a result, the inward force is concentrated on the upper most six centimeter depth of the outside of wall  61 . 
         [0031]    The first beveled surface  53  forms an angle with respect to the inwardly angled surface  55  as shown by indicator δ of from about one hundred thirty four degrees to about one hundred fifty four degrees and preferably about one hundred forty four degrees (meaning that the angle between the face of those surfaces will be between about two hundred six degrees to about two hundred twenty six degrees and preferably about two hundred sixteen degrees). The height of the inwardly angled surface  55  of about five and a half centimeters. The angling of this additional length to the vertical web accomplishes several advantages. First, it facilitates the use of a flange  31  having an inwardly angled first beveled surface  53  for initial contact with the a base container  25  having an outwardly angled upper wall  61  by eliminating the need for the user to stretch the lid  23  about the upper extent of the upper wall  61  like applying a rubber band. Second, the effective vertical angular displacement of first beveled surface  53  as it is brought straight down over the base container  25  is from about sixteen degrees to about thirty six degrees and preferably about twenty six degrees. This gives a force ratio of at least 2:1. This means that any force placed on the lid  23  in the downward direction causes a bending force of twice as much on the flange  31 , at least until the transition between the first beveled surface  53  and inwardly angled surface  55  is reached. 
         [0032]    Once the transition between the first beveled surface  53  and inwardly angled surface  55  is reached, the inward angular displacement of the inwardly angled surface  55  of six degrees greater than the four degree outward tilt of the upper wall  61  facilitates the ease of further movement. This occurs as the sealing area is increased while the main force near the transition between the transition between the first beveled surface  53  and inwardly angled surface  55  maintains the maximum pressure against the upper wall  61 . This produces a sweep sealing action in which a line of maximum sealing is hand, but with significant sealing above the transition between the first beveled surface  53  and inwardly angled surface  55 . 
         [0033]    Also note the more severe upward and across shape as the generally flat floor  37  of the harder plastic portion  33  makes is transition upwardly and to a horizontal orientation before extending into the channel  65 . Compared with the angled portion  39  seen in  FIG. 2 , any lifting of the horizontal web  81  would encounter more resistance by placing bending pressure over a shorter length away from the flange  31 . Thus by comparison, the structure seen at the right of  FIG. 2  actually provide an easier structure and method for removal of the lid  23  from the base container  25 . 
         [0034]    Referring to  FIG. 4 , a perspective view of a further embodiment of the container previously shown in  FIGS. 1-3  is illustrated as a container  91 . Container  91  has many of the same features seen on container  21 , including lid  23 , base container  25 . Container  21  also includes its own outwardly projecting rim  27 , but as will be shown in subsequent figures is associated with a more prominent and more angled structure similar to the slight angled portion  69  seen with container  21 . 
         [0035]    Since container  91  is rectangular shaped, the flange portion  31  has a pair of projecting lips  93  at opposite corners of the lid  23 . This gives a more concentrated lift area even though no part of the generally flat floor  37  of lid  23  of container  91  is seen. 
         [0036]    Referring to  FIG. 5 , a cross sectional view taken along line  5 - 5  of  FIG. 3  is shown. Many of the same elements which appeared in  FIG. 2  are also seen in  FIG. 5 . Notable differences are the provision of a severely angled portion or shelf  95  which si horizontally continuous with the rim  27 . Upper wall  61  is again present, but it extends upwardly from the shelf  95 . A base container wall  97  is seen as extending downwardly from the innermost end of the shelf  95 , whereas the upper wall  61  extends upward from a point slightly off center in a direction toward the outside of the shelf  95 . In effect, the rim  27  forms a thickened outside of the shelf  95  beyond the point at which upper wall  61  rises from the shelf  95 . The use of a shelf  95  as a transition member better allows the outward tilt of the upper wall  61  to exist independent of the tilt of the base container wall  97 . Further, the shelf structure  95  allows for additional reinforcement of the base container  25 . 
         [0037]    Referring to  FIG. 6  an expanded portion of container  91  is seen taken along line  6 - 6  of  FIG. 5 . Most of the structures and angle indications are the same, but it should be noted that the rim capture underside surface  57  is slightly narrower, and that the transition of the generally flat floor  37  from its main extent and into a position where it inters the channel  65  is more abrupt. 
         [0038]    Referring to  FIG. 7  a top view of a container  101  has a lid  103  overlying a base container having a lip  105  with a circular flat floor  107  which is fitted into a flange portion  109  which has a cross sectional width which varies from wide to narrow. The cross sectional width is widest at the midpoint of a lip  111  which may be integrally formed with respect to the flange portion  109 . The cross sectional width is narrowest at the opposite side of the midpoint of lip  111  of lid  103 . 
         [0039]    Instead of providing a raised or gently sloping angled portion  39  as was seen in  FIG. 1  to facilitate manual opening, an additional width of flange portion  109  provides both an additional measure of raised surface and an additional length of flexible material to facilitate ease of opening and closing. Instead of simply providing a platform from which the thumb can lift the outside material, as was the case with angled portion  39 , the provision of both an extended platform co-existent with the level of the flange portion  109  and the provision of an additional peripheral width of flexible flange material  109  to ease manipulation. 
         [0040]    While the present invention has been described in terms of a system and method for providing controlled capture of a lid and base of a sealed container, one skilled in the art will realize that the structure and techniques of the present invention can be applied to many structures, including any structure or technique where an efficient sealing is to be had with a container lid and base and which is stable, and can be operated with less force and more sealing. 
         [0041]    Although the invention has been derived with reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. Therefore, included within the patent warranted hereon are all such changes and modifications as may reasonably and properly be included within the scope of this contribution to the art.