Patent Publication Number: US-2006006178-A1

Title: Tamper-indicating food container lid

Description:
Reference is made to our co pending application. Ser. No. 60/586,073 filed Jul. 8, 2004, to which a claim of priority is made. 
    
    
     BACKGROUND OF THE INVENTION  
      This invention relates generally to the field of wide-mouth food containers, In particular intended for the retail sale of such products as cottage cheese, margarine, and the like. Container and lid could be round or rectangular in shape.  
      Attempts have been made in the prior art to provide a tamper-proof construction, or at least a tamper-indicating lid without the need of complex molding techniques. The most commonly used process is to shrink wrap in the area of the rim of the lid, overlying the mouth of the container. The shrink-wrapping must be broken before the lid can removed. This installation process is troublesome, and requires a separate machine for installation. The opening of the package is also not usually easy, and often requires the use of a tool such as a knife blade. As a result, the process is relatively expensive, and could be somewhat dangerous to the consumer.  
     SUMMARY OF THE INVENTION  
      Briefly stated, the invention contemplates the provision of an improved tamper-indicating package of the type disclosed, in which the need for a separate shrink-wrapping operation is eliminated. To this end, the lid or cover is commonly thermoformed from sheet material or injection molded to include a vertical skirt with a peripheral portion of thin walled cross section to allow flexing of a part of the rim over an outwardly-extending bead on the container. The skirt includes a tear strip forming a manually-engageable tab. A portion of the strip below the skirt engages a bead on the container, and may be heat sealed if desired, or allowed to fall free from the container after the tear strip is separated. The container at the mouth thereof includes a corresponding flexible skirt with an outwardly flared edge to engage the skirt of the lid. The tear strip is preferably formed by using laser beams which also form the manually-engageable tab. After a first opening of the container, it is closed in normal manner using a plug-type sealing means on the lid which engages a corresponding recess on the inner surface of the container mouth.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In the drawings, to which reference will be made in the specification, similar reference characters have been employed to designate corresponding parts throughout the several views.  
       FIG. 1  is a fragmentary sectional view of a lid or cover element comprising an embodiment of the invention.  
       FIG. 2  is a fragmentary sectional view of a corresponding container element.  
       FIG. 3  is perspective view of a round lid on a container with a tab  
       FIG. 4  is a perspective view of a complete lid with two complete circumferential slit lines with a tab  
       FIG. 5  is an enlarged fragmentary perspective view showing a line of slitting to form an opening tab on a lid with two circumferential slit lines  
       FIG. 6  is a perspective view of a complete lid with one complete circumferential slit line with a tab  
       FIG. 7  is an enlarged fragmentary perspective view showing a line of slitting to form an opening tab on a round lid  
       FIG. 8  is a perspective view of a rectangular lid with two complete circumferential slit lines with a tab  
       FIG. 9  is an enlarged fragmentary perspective view of slitting to form an opening tab on a rectangular lid  
    
    
     DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENT  
      In accordance with the invention, the device, generally Indicated by reference character  10  comprises broadly: a container element  11  and a lid or cover element  12 .  
      The container element  11  may be of known type, commonly formed by injection molding or thermoforming. It includes a bottom wall  20 , an arcuate side wall  21 , an upper rim section  22 , and a lid-engaging portion  23  forming upper and lower recesses  24  and  25 . It also includes a radially-extending recess  26  supporting a horizontal portion  27  and a bead-forming portion  28  defining an annular recess  29  engaged by the lid element upon first installation.  
      The lid element  12 , commonly formed as a thermoforming or injection molding operation, and includes a horizontal main wall  30 , an inner rim member  31 , a radially-extending wall  32  and an outer rim member  33 . The rim member  33  includes a single or multiple lines of slitting  34 , preferably formed using a Laser beam, and as seen in  FIG. 3 , include an outwardly-oriented portion to form a manually-engageable tab  35 .  
      During an initial opening operation, the user first separates the tab  35  and moves the same circumferentially to result in severing that portion of the slitted lines  34  which lie in a horizontal plane. This motion will also separate that portion of the lid  38  located below the horizontally-slitted lines so that it will fall away from the container. When the lid is replaced, there will be visually observable evidence that the container was initially opened. If desired, the portion  38  may be heat sealed in position to remain after the lid is removed.  
      It may thus be seen that we have invented novel and highly useful improvements in lid construction for wide-mouth containers in which the need for heat shrinking additional material surrounding the rim of the lid is eliminated. The novel lid construction is commonly thermoformed or injection molded. The lower flared portion of the lid forms the locking means which, at the time of installation, radially expands past the outermost mouth dimension of the container, and contracts beneath the rim of the container to provide a locking means. By laser slitting not only the horizontal parting lines, but forming a manually-engageable tab, those portions of the lid located below the horizontal slitting line will be ruptured at the time of opening and fall away from the container, leaving clear evidence of an initial opening of the container.  
      It is noted that after first opening, the lid is removably sealed in the container mouth and maintained by engagement of members  31  and  33  with members  23 ,  26 , and  28 .  
      It may thus be seen that we have invented novel and highly useful improvements in a combination lid and container, in which the need for a heat shrinking operation is eliminated while providing a visual indication that the container may have been tampered with by the time it reaches the consumer. This is accomplished by providing the lid with a downwardly-extending flared member which may be stretched over a bead on the container rim to subsequently contract when the lid is fully seated. The flared portion is provided with a tear strip which must be removed before the lid can be manually removed, and the removal of the tear strip forms a gap which is readily observable. Optionally, with the provision of vertical slitting to form a manually-engageable tab on the tear strip, the slitting may be continued into the area below the tear strip so that it will fall away from the container at the same time. Until the tear strip has been removed, it is difficult to remove the lid from the container.  
      We wish it to be understood that we do not consider the invention to be limited to the precise details shown and described in the specification, for obvious modifications will occur to those skilled in the art to which the invention pertains.