Abstract:
The present invention relates to a container with a lid and more particularly to improvements in providing a durable leak-resistance sealing means between the container and lid.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    The present invention relates to a container with a lid and more particularly to improvements in providing a durable leak-resistance sealing means between the container and lid. 
       BACKGROUND OF THE INVENTION 
       [0002]    Package suitable for the transport of e.g. inflammable liquids require a very strict demands. They must pass internal pressure and hydraulic strict requirements for the packaging of dangerous goods under specific categories. 
         [0003]    Conventional containers that meet the above mentioned criteria incorporate a resilient sealing member such as a silicon rubber O-ring seal, to achieve maximum seal by loading the said seal under compression on the junction position between the container and lid. 
         [0004]    A prior art example is the arrangement of the container with a lid found in EP 1254056. 
         [0005]    The known arrangements, including the one proposed in EP 1254056, are designed in such a way that the compression of the O-ring seal depends on the stacked load over the closed container. This means that the O-ring seal could not perform as expected as its deformation could be either too little (risk of leakage) or too high when heavier loads (consequent damage of the O-ring). 
         [0006]    This kind of designs allocates the O-ring in between the top edge of the container and a sealing groove of the lid, therefore any vertical load being applied to the lid is directly and fully supported by the O-ring itself. 
         [0007]    The practice has demonstrated that the O-ring, usually made from synthetic rubber, does not guarantees that the container and lid assembly be able to withstand high lateral and vertical impacts. This situation can arise for example when the container filled with liquid is dropped at 45° or dropped on its longitudinal axis. 
         [0008]    A primary objective of the present invention is to provide a container and lid featured to overcome this problem. 
         [0009]    Another object of the present invention is to provide an improved container and lid that withstands the performance criteria according to the requirements set forward by the UN (United Nations) and/or ADR regulations for transportation of dangerous products. 
         [0010]    Explanation of the Invention 
         [0011]    The invention discloses an improved container with a lid, the container body having an open top with a rim thereon and at least one annular flange extending radially outwards from an external wall of the container body, and the lid comprising a central disc-shaped portion and an inverted U shaped peripheral channel for receiving the rim of the container, said peripheral channel being defined by an inner leg connected to the central disc-shaped portion, a bottom wall and an outer leg including at least one annular rib formed therein in a relationship corresponding to the annular flange of the container body, the annular rib of the lid being snap-fastenable over the corresponding said annular flange of the container body, the container further comprising a resilient sealing member, which extends around the entire peripheral channel of the lid. 
         [0012]    The improvement comprises a rim configured such that there is no significant gap between the rim and the bottom wall of the peripheral channel when the rib of the outer leg of the said peripheral channel is tightly engaged upon its corresponding annular flange of the container, providing to the resilient member a constant compression irrespective of any subsequent load applied to the lid, particularly to the central disc-shaped portion of the lid. 
         [0013]    The inventors solved that the resilient sealing members in conventional arrangements do not always perform elastically under loading conditions, and specifically in cases where the load over the lid is too heavy, because under said circumstances the load causes a strain on the material that forms the resilient sealing member over his yield point causing a permanent plastic deformation of said material. Consequently, the O-ring will never perform as before. 
         [0014]    The invention overcomes this problem by limiting the strain (and the stress) of the resilient sealing member within his elastic limit. 
         [0015]    Naturally, the selection of a rim configuration to fulfil the requirements of the claimed invention must be done in conjunction with a proper selected suitable size of the resilient sealing means to make them work under the most efficient strain according to his specifications and always within his elastic limits. The result is a long term sealing and independent from container storage or handling conditions. 
         [0016]    In one embodiment of the invention the number of flanges and the number of ribs is more than one. Specifically the container body has a plurality of annular flanges spaced apart and extending radially outwards from an external wall of the container body, and the outer leg of the lid also includes a plurality of annular ribs formed therein but in a relationship corresponding to the spaced apart relationship of the annular flanges of the container body. In this embodiment the annular ribs of the lid are snap-fastenable over the corresponding said annular flanges of the container body and the rim is configured such that there is no significant gap between the rim and the bottom wall of the peripheral channel when the uppermost rib of the outer leg is tightly engaged upon its corresponding annular flange of the container. 
         [0017]    According to another feature of the invention, on the underside of the bottom wall of the peripheral channel there is provided an annular downwardly oriented rib that configures together with the inner leg of the peripheral channel a reception groove for the rim, said reception groove being dimensioned such that the rim fits tightly onto the reception groove. 
         [0018]    In a preferred embodiment, the upper face of the uppermost annular flange of the container exhibits an annular projection adapted to compress the sealing member that is enclosed within the space delimited by the annular downwardly oriented rib, the bottom wall and the outer leg of the peripheral channel of the lid. 
         [0019]    According to this particular embodiment, the resilient sealing member is protected from the cutting effect of the rim or uppermost terminal edge of the container, which can act as sharp wedge. 
         [0020]    In accordance with another feature of the invention, the distal end of the annular projection forms an acute angle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]      FIG. 1 , is a side sectional view of the lid as secured onto a container. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0022]    Referring to the drawing of  FIG. 1 , this figure illustrates an injection moulded cylindrical container  1  body and injection moulded lid  2  which embodies the present invention. 
         [0023]    The container  1  has an open top with a rim  3  thereon and two annular flanges  4  and  5  spaced apart and extending radially outwards from the external wall  6  of the container body. These annular flanges  4 ,  5  provide to the container  1  a double lock as will be explained in more detail hereafter. 
         [0024]    The lid  2  is of the type comprising a central disc-shaped portion  7  and an inverted U shaped peripheral channel  8  for receiving the rim  3  of the container  1 . The peripheral channel  8  is defined by an inner leg  15 , connected to the central disc-shaped portion  7 , a bottom wall  13  and an outer leg  9 . This outer leg  9  includes a two of annular ribs  10 ,  11  formed therein in a relationship corresponding to the spaced apart relationship of the annular flanges  4  and  5  of the container body. As usual, the annular ribs  10 ,  11  of the lid  2  are snap-fastenable over the corresponding said annular flanges  4 ,  5  of the container body. 
         [0025]    The container  1  further comprises a resilient sealing member  12 , made of a pressure sensitive hotmelt adhesive consisting essentially of a synthetic rubber, for example Technomelt 8797 provided by Teroson®, which extends around the entire peripheral channel  8  of the lid  2 . 
         [0026]    As will be appreciated in  FIG. 1 , the rim  3  is configured such that there is no significant gap between the rim  3  and the bottom wall  13  of the peripheral channel  8  of the lid  2  when the said lid  2  is secured onto the container  2  in a sealed position, this is to say when the uppermost rib  10  of the outer leg  9  of the said peripheral channel  8  is tightly engaged upon its corresponding annular flange  4  of the container. 
         [0027]    All the flanges and ribs described above are integrally made with the container and lid, respectively. 
         [0028]    This particular arrangement provides to the resilient member  12  a constant compression irrespective of any subsequent load applied to the lid  2 , particularly to the central disc-shaped portion  7  of the lid  2  when for example a stack of filled containers is formed over a bottom closed container. 
         [0029]    A skilled in the arts knows that plastic parts made by injection are subject to shrinkage due to the moulding process itself (in addition to their own expansion/shrinkage due to temperature, hygroscopic effects and so on). Therefore engineers use to introduce small design tolerances that allow absorb these deviations and ensure the suitable coupling between container and lid engagement surfaces. 
         [0030]    Thus, in the context of the present invention the lack of a significant gap must be construed as a lack of an intentional gap between the uppermost terminal edge of the rim  3  and the faced portion of the bottom wall  13  of the peripheral channel  8  of the lid. In practice, a gap equal or less than 0.2 mm it is considered a non significant gap. 
         [0031]    In the preferred embodiment of  FIG. 1 , there is shown that on the underside of the bottom wall  13  of the peripheral channel  8  there is provided an annular downwardly oriented rib  14  that configures, together with the inner leg  15  of the peripheral channel  8 , a reception groove  16  for the rim  3 . The reception groove  16  is dimensioned such that the rim  3  fits tightly onto the reception groove  16 , contributing to the leak resistance of the lid  2 . This tightly fitting performs in fact as a third sealing look for the container  1  and lid  2 . 
         [0032]    A forth sealing look is formed by the resilient sealing member  12  itself, confined in a space delimited by the annular downwardly oriented rib  14  of the bottom wall  13  of the peripheral channel  8  of the lid  2 ; the outermost portion of the said bottom wall  13  and the outer leg  9  of the mentioned peripheral channel  8  of the lid  2 . 
         [0033]    As seen in  FIG. 1 , the upper face  17  of the uppermost annular flange  4  of the container  1  exhibits an annular projection  18 , which forms an acute angle, adapted to compress the sealing member  12  and to favour the retention of the resilient sealing member  12  in its optimum place. 
         [0034]    Once the lid  2  is secured onto the container  1 , for subsequent removal of the lid  2  the user will tear off a finger tip width removable tearable skirt part (not shown) of the external circumferential skirt  19  of the container whereby after removal thereof he can apply by means of a tool an upward and radially outward directed force onto the lower edge portion of the outer leg  9  of the lid  2 , in order to disengage the lid  2  from the container  1 .