Abstract:
A molded plastic container, such as a five gallon pail, that includes a lid and main body that are selectively attachable to each other without a resilient gasket. The main body of the plastic container includes a flexible sealing finger formed along the top rim of the main body. The flexible sealing finger is received within a sealing chamber formed as part of the rim. The sealing chamber is defined by a gland seal such that when the lid is attached to the main body, both the flexible finger and the gland seal can deflect to create multiple sealing points between the flexible sealing finger and the sealing chamber. A latch ring is formed on the outer surface of the main body and engages a locking tab formed on the lid to hold the flexible finger in the sealing chamber.

Description:
BACKGROUND OF THE INVENTION 
     The present invention generally relates to a cylindrical container having an open end sealed by a removable and resealable lid. More specifically, the present invention relates to a plastic cylindrical container and lid assembly that form a generally liquid and vapor tight seal without the use of a resilient gasket. 
     Presently, many designs for plastic buckets or containers that include a removable and resealable lid exist for the storage of liquids, such as paint or other chemical compounds. Many of these container and lid assemblies are formed in a conventional five-gallon size, which has become an accepted and common container size for the storage and delivery of liquid materials, such as paint. 
     Since many of these plastic containers store liquids during transport and for extended durations prior to use or following use, it is important that the lid and container form a liquid and vapor tight seal to prevent leakage during shipment and to prevent or limit the contents of the container from being affected by the ambient atmosphere. In a very common prior lid and container assembly, a resilient gasket is positioned between the container lid and the container body. When the lid is attached to the body, the gasket is compressed to create a liquid and vapor seal between the container body and the lid. 
     Although the use of a resilient gasket between the container body and lid has proven to be an effective way to create both a vapor and liquid seal, the inclusion of the resilient gasket within the container assembly requires additional processing steps, thereby increasing the cost and complexity of creating the plastic container. Therefore, a need exists for a plastic container assembly that provides a liquid and vapor seal between the container main body and the lid without requiring a gasket. Further, a need exists for a plastic container assembly that can be molded and formed using conventional techniques. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a plastic cylindrical container, such as a five gallon pail, that is formed by injection molding and includes a lid that is removably attachable to a main body to provide a liquid and vapor tight seal without the use of a gasket. 
     The cylindrical main body includes an open top end that is defined by a circumferential lip. The circumferential lip includes a flexible sealing finger that has a width extending between a first sealing protrusion and a second sealing protrusion. The flexible sealing finger is pivotally integral to the container sidewall by a flexible neck such that the sealing finger can flex during attachment of the lid to the main body. The main body of the plastic container includes a latch ring extending outward from an outer surface of the container sidewall to hold the lid onto the main body. 
     The plastic container further includes a lid that is adapted to be received on the open top end of the main body. The lid includes a top wall connected to a circumferential inner sidewall. The inner sidewall is joined to an outer sidewall by a horizontal connector portion that extends transverse to both the outer sidewall and the inner sidewall. A gland seal extends from the connector portion at a location between the inner sidewall and the outer sidewall such that the gland seal and the inner sidewall define a sealing chamber. The width of the sealing chamber between the gland seal and the inner sidewall is slightly less than the width of the flexible sealing finger formed as part of the main body in order to create sufficient contact pressure for a liquid and vapor seal. 
     The outer sidewall of the lid is spaced from the gland seal to define a flexing chamber. The first end of the outer sidewall includes a locking tab. When the lid is installed on the main body, the locking tab of the outer sidewall engages the latch ring to retain the lid on the main body and hold the flexible sealing finger within the sealing chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings illustrate the best mode presently contemplated of carrying out the invention. 
       In the drawings: 
         FIG. 1  is a perspective view of a cylindrical plastic container including a container main body and a lid constructed in accordance with the present invention; 
         FIG. 2  is a front view of the plastic container; 
         FIG. 3  is a section view illustrating the interaction between the main body of the container and the lid; 
         FIG. 4  is a view similar to  FIG. 3  illustrating one of the strengthening ribs contained within the lid; 
         FIG. 5  is an exploded, section view illustrating the lid and main body of the container; and 
         FIG. 6  is a magnified view of the flexible sealing finger formed on the top lip of the main body illustrating the pivoting motion of the sealing finger during attachment of the lid to the main body. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a plastic container  10 . In the embodiment illustrated in  FIG. 1 , the plastic container  10  has a capacity of five gallons, although other sizes are contemplated as being within the scope of the present invention. The plastic container  10  includes a cylindrical main body that receives a lid  14 . The main body  12  includes a cylindrical container sidewall  16  that is joined at its bottom end to a bottom wall  18 . In the embodiment shown in  FIG. 2 , the container sidewall  16  includes a first satellite ring  20  and a second satellite ring  22  that provides additional support for the container wall  16 . 
     The lid  14  shown in  FIG. 1  is sized to be received on the container main body  12  and includes a top wall  24  that extends across the open interior of the container  10  defined by the main body  12 . The top wall  24  defines a generally planar top surface that includes an optional opening  26  for adding to the contents of the assembly (pigments, etc.) or for pouring the contents out of the container without removal of the lid  14 . 
     The lid  14  includes a series of separate locking sections  28  spaced along the outer circumference of the lid. Each of the locking sections  28  are separated by an open groove  30  that allows each of the locking sections  28  to be moved independently from the other locking sections  28 . As illustrated in  FIG. 1 , a tear strip  32  joins the bottom edge  33  of each of the locking sections  28  to restrict removal of the lid  14  from the main body  12 . When the container  10  is opened for the first time, the tear strip  32  is removed from the lid  14  to permit the locking sections  28  to be separately lifted to permit removal of the lid  14  from the main body  12 . Once the tear strip  32  has been removed, the lid  14  can be repeatedly removed and reattached to the main body  12 , as is conventional. 
       FIGS. 3-5  illustrate the detailed configuration of both the lid  14  and the main body  12 , both before attachment of the lid  14  to the main body  12  and after the lid  14  has been securely attached. Referring first to  FIG. 5 , the container sidewall  16  is a generally cylindrical element having an outer surface  34  and an inner surface  36 . The container sidewall  16  extends from the bottom wall ( FIG. 1 ) to a top lip  38 . The top lip  38  defines an open top end  40  of the main body  12 , through which liquid can be removed and supplied into the open interior  42  defined by the main body in addition to the opening  26 . In the embodiment illustrated, both the first satellite ring  20  and the second satellite ring  22  extend at an angle from the outer surface  34 . The first satellite ring  20  includes a vertical skirt  44  spaced from the outer surface  34  to define a finger cavity  46  that aids in lifting and carrying the plastic container  10 . Although both of the first and second satellite rings  20 ,  22  are shown in the Figures, it is contemplated that either or both of these elements could be removed from the plastic container  10  or additional rings added. 
     As illustrated in  FIG. 5 , the top end of the main body  12  includes a flexible sealing finger  48  integrally formed with the main body  12 . The sealing finger  48  is integrally formed with the container wall  16  and is configured to flex and rotate as the lid  14  is attached to the main body  12 . Referring now to  FIG. 6 , the flexible sealing finger  48  includes a first sealing protrusion  50  and a second sealing protrusion  52  that define the width W of the flexible sealing finger  48 . As can be understood in  FIG. 6 , the first sealing protrusion  50  extends past the outer surface  34  while the second sealing protrusion  52  extends past the inner surface  36  of the container wall  16 . The flexible finger  48  is attached to the container wall  16  at a flexible neck  54  having a reduced material thickness that allows the flexible finger  48  to pivot in the direction shown by arrow  56 , as will be described in much greater detail below. 
     Referring back to  FIG. 5 , the main body  12  further includes an annular latch ring  58  that extends from the outer surface  34  of the container wall  16 . The latch ring  58  is positioned slightly below the flexible sealing finger  48  and extends at approximately a 45° angle from the outer surface  34  to an outer end  60 . The outer end  60  is spaced from the outer surface  34  to define an annular cavity  62 . Referring now to  FIG. 3 , at spaced locations around the outer circumference of the container wall  16 , the annular cavity  62  is filled with plastic material to define a support rib  64  to increase the stiffness and stability of the latch ring  58 . In the embodiment of the invention illustrated, it is contemplated that the outer circumference includes support ribs  64  equally spaced around the outer circumference of the main body, although the number of support ribs  64  can vary based upon the design of the container. 
     In the embodiment illustrated in  FIG. 5 , the entire main body  12  is formed from a single, molded plastic component that includes all of the features previously described. The single, molded plastic main body  12  can be economically manufactured utilizing conventional molding techniques. However, it is contemplated that other materials besides plastic could be utilized to form the main body  12  while operating within the scope of the present invention. 
     As illustrated in  FIG. 5 , the lid  14  is sized to be received and retained by the main body  16  to close the open interior  42  of the main body  12  along the top end  40  defined by the top lip  38 . The lid  14  includes the top wall  24  that is generally perpendicular to the container sidewall  16  and extends completely across the open interior  42  defined by the container sidewall  16 . The top wall  24  is a generally horizontal member that is integrally formed with an inner sidewall  66  through a connecting web  68 . The inner sidewall  66  is a generally vertical member that is joined at its first end  70  to the connecting web  68  and is joined at its second end  72  to a horizontal connecting portion  74 . The connecting portion  74  defines an annular top edge  76  for the lid  14  and is joined to a second end  78  of an outer sidewall  80 . The outer sidewall  80  extends vertically downward to a first end  82  that defines a locking tab  84 . As previously described, the tear strip  32  is attached to the locking tab  84  formed on the first end  82  of the outer sidewall  80  along a line of weakness  86 . The line of weakness  86  allows the tear strip  32  to be easily removed from the outer sidewall  80  as desired. 
     As shown in  FIG. 5 , the outer sidewall  80  is generally parallel to the inner sidewall  66  and defines a receiving cavity  88 . The receiving cavity  88  formed between the outer sidewall  80  and the inner sidewall  66  is sized to receive the flexible sealing finger  48  and the latch ring  58 , as can be seen in both  FIGS. 3 and 4 . 
     Referring back to  FIG. 5 , the lid  14  further includes a gland seal  90  that extends downward from the connecting portion  74  into the receiving cavity  88 . The gland seal  90  is an annular wall that is spaced from the inner sidewall  66  to define an open sealing chamber  92 . Further, the gland seal  90  is spaced from the outer sidewall  80  to define a flexing chamber  94 . The bottom end  96  of the gland seal  90  is spaced above the locking tab  84  such that the receiving cavity  88  can receive the latch ring  58  between the bottom end  96  of the gland seal  90  and the locking tab  84 , as best seen in both  FIGS. 3 and 4 . 
     In the embodiment of the invention shown in  FIG. 5 , the gland seal  90  has a reduced material thickness as compared to the inner sidewall  66  such that the gland seal  90  can be flexed to a small degree upon insertion of the main body  12  into the lid  14 . The slight deflection of the gland seal  90  allows for improved sealing between the flexible sealing finger  48  and the inner sidewall  66  and the gland seal  90 . 
     Although the embodiment of the invention shown in the Figures includes the gland seal  90  between the inner sidewall  66  and the outer sidewall  80 , it is contemplated that the gland seal  90  could be eliminated in alternate embodiments. In such a configuration, the thickness of the outer sidewall  80  could be expanded above the locking tab  84  to create the sealing chamber  92 . In such an embodiment, the sealing chamber  92  would have a much more rigid dimension as compared to the embodiments shown in  FIG. 5  that includes the gland seal  90 . 
     As can best be seen in  FIG. 4 , the flexing chamber  94  is partially filled at several locations by a plastic material that defines a support rib  98 . A series of support ribs  98  are spaced along the circumference of the flexing chamber  94  to provide support and stability for the gland seal  90 . 
     Referring back to  FIG. 5 , the sealing chamber  92  has a uniform width around the entire circumference of the lid  14  that is defined by the distance between the outer surface  100  of the inner sidewall  66  and the inner surface  102  formed as part of the gland seal  90 . The width of the sealing chamber  92  is selected to be slightly less than the width W of the flexible sealing finger  48  shown in  FIG. 6 . Thus, when the lid  14  is pressed onto the main body  12 , the flexible sealing finger  48  pivots as shown by arrow  56  in  FIG. 6 . Upon rotation, the first sealing protrusion  50  is pressed into contact with the inner surface  102  of the gland seal  90  while the second sealing protrusion  52  is held into sealing contact with the outer surface  100  of the inner sidewall  66 . The pivoting rotation of the flexible sealing finger  48  about the flexible neck  54  allows the flexible finger  48  to create at least two points of contact between the flexible sealing finger  48  and the inner sidewall  66  and gland seal  90 . 
     Referring now to  FIGS. 3 and 4 , when the lid  14  is installed onto the main body  12 , the flexible sealing finger  48  is received within the sealing chamber  92  formed between the gland seal  90  and the inner sidewall  66  of the lid  14 . As described with reference to  FIG. 6 , the flexible finger  48  rotates to create a plurality of ring contact seals with the lid, as previously described. 
     As the lid  14  is pressed downward onto the main body  12 , the latch ring  58  deflects downward and inward and the outer sidewall  80  deflects outward until the outer end  60  of the latch ring  58  passes over the locking tab  84 . Once the outer end  60  of the latch ring  58  passes over the locking tab  84 , the outer end  60  is retained by a latching shoulder  104  formed as part of the locking tab  84 . The latching shoulder  104  prevents the latch ring  58  from leaving the receiving cavity  88  unless the outer sidewall  80  is pulled outward. Further, the interaction between the latch ring  58  and the locking tab  84  holds the flexible sealing finger  48  within the sealing chamber  92  to insure the multiple sealing points between the flexible sealing finger  48  and the gland seal  90  and inner sidewall  66 . 
     Once the lid  14  has been installed onto the main body  12 , the tear strip  32  can be separated from the outer sidewall  80 . Once the tear strip  32  has been removed, each of the individual locking sections  28  ( FIG. 1 ) can be pulled outward and upward to release the interaction between the latch ring  58  and the locking tab  84  ( FIG. 4 ). 
     Referring back to  FIG. 3 , when the lid  14  is installed onto the main body  12 , the generally planar outer surface  100  of the inner sidewall  66  contacts the inner surface  36  of the container wall  16  over the entire length of the inner sidewall  66  from a junction point  106  to the flexible neck  54  of the sealing finger  48 . The contact between the inner sidewall  66  and the container sidewall  16  limits the amount of liquid that can become entrapped between the lid  14  and the main body  12 . When the plastic container  10  is used with paint or other material that hardens when it dries, the contact between the inner sidewall  66  and the container sidewall  16  prevents liquid from becoming entrapped between the lid and main body, thereby preventing the liquid from entering between the lid and main body, drying and falling back into the storage supply within the container. 
     Although the embodiment of the invention shown and described in the Figures is described as being formed from a plastic material having a size to store and contain five gallons of a liquid, it is contemplated that various other materials could be utilized and the container could be formed of varying sizes. 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.