Patent Publication Number: US-2007108210-A1

Title: Can plastic lid having a tamper evident portion

Description:
FIELD OF THE INVENTION  
      The present invention refers to an improved plastic lid for closing a can, obtained in a metallic sheet and which is of the type comprising a tubular body, with its lower edge affixing or incorporating a bottom wall and with its upper edge carrying, directly by means of a deformed portion of the tubular body or by means of an annular upper wall portion, a seat for the seating and retention of the press-fit lid. Particularly, the invention refers to the provision of a plastic lid for a can of the type considered above and which is used for containing products of progressive consumption, such as certain food articles.  
     BACKGROUND OF THE INVENTION  
      Determined products, such as certain food articles, have to be submitted to a hermetic storage and provided with a clear visual indication to the consumer that the container in which they are presented to the market has not been violated. Since many of these products are of progressive consumption, it is indispensable that after the first opening of the container, the lid, which gives access to the inside of the can, may be reclosed as many times as necessary during the progressive consumption of the stored product, in order to guarantee the tightness of the reclosed can and to protect the remaining content thereof.  
      Patent application PI0203950 (PCT/BR03/00030) of the same applicant discloses a plastic lid construction comprising, in a single piece: a sealing portion which is removably seated and retained in a seat medianly provided in an annular upper wall which has its external edge usually double seamed to the upper end of the tubular body; and a tamper evident portion, comprising a lower skirt to be seated around the upper end of the tubular body, and an upper ring, seated on the upper end of the tubular body and which is incorporated, externally, to the lower skirt and, internally, through breakable radial bridges, to an upper end of the sealing portion, which projects radially outwardly from the seat. The tamper evident portion presents an interruption extending along the width of the upper ring and along at least part of the height of the lower skirt, along which is lodged a gripping tab which, when pulled, after the rupture of the tamper evident portion, allows achieving an easy and controlled opening of the lid.  
      The construction described above results in a reclosable plastic lid, of simple construction and relatively low cost, incorporating a gripping tab which facilitates the opening, as well as a reliable seal element which permits the prompt visualization of violation.  
      The prior constructive solution cited above is particularly adequate for the closure of cans used to contain products of progressive consumption, whose lids are not subject, during the closure, storage and shipping operations of said cans, to impacts, in the axial opening direction, in relation to other cans or to storage and handling means.  
      It has been verified in these known cans that, when the lower skirt of the tamper evident portion is submitted to certain involuntary ascending axial forces and displacements, at least some of the radial bridges, which are located closer to the region submitted to said forces, are broken, indicating, through the partial (but visible) damage caused to the seal element, that the content of the can has been violated, which, in these cases, has not really occurred.  
      In brief, the construction of the seal defined in PI0203950-8 is susceptible to involuntary ruptures in determined handling conditions to which the can is submitted.  
     OBJECT OF THE INVENTION  
      The object of the invention is to provide a reclosable plastic lid for the type of can considered herein and such as described in the patent application cited above, but presenting an improved construction, according to which the tamper evident portion becomes more resistant to involuntary ruptures when the plastic lid is submitted to certain usual forces and impacts during the closure, storage and shipping operations of said closed cans.  
     DISCLOSURE OF THE INVENTION  
      The improvement of the present invention is directed to a lid which comprises, in a single piece, a sealing portion, removably seated and retained in the seat and which is provided with an external edge projecting radially outwardly from the seat; a tamper evident portion comprising a lower skirt, to be seated around part of the upper end of the tubular body and which is superiorly incorporated, through bridges, to the external edge of the sealing portion, the tamper evident portion presenting an interruption extending along at least part of the height of the lower skirt, the sealing portion incorporating, at its external edge, a gripping tab projecting through said interruption of the tamper evident portion, said bridges being broken when submitted to a certain pulling force, which separates the tamper evident portion from the sealing portion upon the first opening of the lid.  
      According to the invention, the breakable bridges are axially disposed around a circumferential extension of the upper end of the tubular body of the can, in order to connect an upper end of the lower skirt with the external end of the sealing portion in points which are angularly spaced from each other.  
      According to the improved construction, the sealing portion extends radially, until the peripheral edge of the upper end of the tubular body of the can, superiorly covering and protecting the can, and having its external edge incorporating, inferiorly, through a plurality of breakable axial bridges, the lower skirt of the tamper evident portion.  
      The new axial arrangement of the breakable bridges, generally seated around the upper end of the tubular body of the can, makes said bridges be submitted to a compressive force and not to a pulling force, when the lower skirt is forced upwardly, by impact of the lid against any other element, resisting much better to said forces and avoiding the undue rupture thereof. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention will be described below, with reference to the appended drawings, in which:  
       FIG. 1  is a perspective view of a plastic lid constructed according to an embodiment of the present invention and incorporating a tamper evident portion;  
       FIG. 2  is an exploded perspective view of the lid of  FIG. 1 , after the rupture of the tamper evident portion;  
       FIG. 3  is an upper plan view of the plastic lid illustrated in  FIG. 1 ;  
       FIG. 4  is a partial diametrical cross-sectional view of the lid illustrated in  FIGS. 1-3  and mounted to the upper end of a can, said section being taken according to line IV-IV of  FIG. 3 ; and  
       FIG. 5  is a view similar to that of  FIG. 4 , but with the section being taken according to line V-V of  FIG. 3 . 
    
    
     DESCRIPTION OF THE ILLUSTRATED EMBODIMENT  
      According to the illustrated embodiment, the present lid can be applied to a metallic sheet can comprising a tubular body  10 , with a lower end  11  securing a bottom wall  12  and with an upper end  13  securing, by a double seam  14 , an annular upper wall  15 , which defines, internally, a seat  16  for the hermetic seating of the lid  20 .  
      The annular upper wall  15  can take the form of a structural ring, as illustrated in  FIGS. 4 and 5 , or the form of an annular plate in the cans with great dimensions, such as the 18-liter cans.  
      The construction of both the annular upper wall  15  and the seat  16  may be achieved by different manners, provided that it allows for a hermetic and secure fitting of the lid  20  to the upper part of the can. In  FIGS. 4 and 5 , the construction of the annular upper wall  15  and the seat  16  is accomplished as described and claimed in patent application PI 9408643-5 granted to the same applicant in Brazil and in other countries (in the U.S. Pat. No.  5 , 899 , 352  and in Europe, EPO 0706486), and therefore will not be described in details in the present disclosure.  
      According to the invention and as illustrated in the appended drawings, the lid  20  is preferably constructed in plastic material, transparent or not, comprising a sealing portion  21  of adequate construction, so as to be removably seated and retained in the seat  16 , said sealing portion  21  presenting an external edge  21   b  which is seated on the upper end  13  of the tubular body  10  of the can. The lid  20  further comprises, in a single piece with the sealing portion  21 , a tamper evident portion  25  having a lower skirt  25   a  which is generally tightly seated around a circumferential extension of the upper end  13  of the tubular body  10 , more particularly its double seam  14 , and presenting an upper end  25   b  which is incorporated, by means of manually breakable bridges  26 , to the external edge  21   b  of the sealing portion  21 . The bridges  26  connect the upper end  25   b  of the lower skirt  25   a  with the external edge  21   b  of the sealing portion  21  in points which are angularly spaced apart.  
      According to the present invention, the bridges  26  are broken when submitted to a certain pulling force, which separates the tamper evident portion  25  from the sealing portion  21 , upon the first opening of the lid  20 .  
      The tamper evident portion  25  presents an interruption  25   c , in its circumferential extension, extending along at least part of the height of the lower skirt  25   a , said interruption  25   c  defining a certain circumferential spacing between respective confronting edges of the lower skirt  25   a , on both sides of the interruption  25   c.    
      According to the present invention, the sealing portion  21  incorporates a gripping tab  27 , axially downwardly projecting through said interruption  25   c  of the tamper evident portion  25 , for example remaining substantially leveled with the lower skirt  25   a.    
      In the illustrated embodiment, the gripping tab  27  projects along the whole axial extension of the lower skirt  25   a , but it can also project axially inferiorly beyond the axial extension of the lower skirt  25   a.    
      According to the present invention, the tamper evident portion  25  comprises at least one breakable lock  28 , connecting the griping tab  27  with the lower skirt  25   a . The gripping tab  27  is manually operable only upon the rupture of part of the tamper evident portion  25 , for example, upon the rupture of each breakable rod  28 .  
      In the illustrated construction, the lower skirt  25   a  incorporates the ends of a bridge  25   d , circumferentially extended over the interruption  25   c  of the tamper evident portion  25  and over the gripping tab  27 . The bridge  25   d  presents a first end  25   e , which is incorporated to the lower skirt  25   a  by connecting means  25   f , which are broken when said first end  25   e  is forced away from the lower skirt  25   a , for example, by being pulled radially outwardly from, in order to liberate the manual access to the gripping tab  27 . In the illustrated embodiment, the bridge  25   d  has its first end  25   e  superposed to said lower skirt  25   a  and incorporated to the latter by two connecting means  25   f , which are circumferentially spaced from each other.  
      The gripping tab  27  is inferiorly incorporated to the bridge  25   d  through a breakable lock  28 , in the form of one or more axial bridges, which are manually broken upon the first opening of the lid.  
      The provision of the gripping tab  27  allows the sealing portion  21  to be easily removed from its seating condition on the seat  16 , and also a controlled and progressive opening of the can, first in the region adjacent to the gripping tab  27 , and subsequently in the remaining of the seat, preventing the stored product from being inadvertently taken out from the can.  
      According to the present invention, the gripping tab  27  may present one of the massive and at least partially perforated forms, defining a tag, such as in the illustrated construction.  
      It should be understood that the gripping tab  27  can be massive and formed from a respective portion of the lower skirt  25   a , remaining perfectly leveled with the latter and maintaining a gap  29  therebetween.  
      In the illustrated construction, the external edge  21   b  of the sealing portion  21  incorporates a small cylindrical lower flap  21   c , which surrounds, preferably tightly, a circumferential extension of the upper end  13  of the tubular body  10  and from which the bridges  26  depend, being inferiorly incorporated to the upper end  25   b  of the lower skirt  25   a.    
      It is also possible, as illustrated, for the lower skirt  25   a  to incorporate a circumferential internal projection  25   h , axially spaced from the external edge  21   b  of the sealing portion  21  and which is dimensioned to be seated and axially locked under the double seam  14  at the upper end  13  of the tubular body  10  and around the latter.  
      In a constructive form, the external edge  21   b  of the sealing portion  21  incorporates an upper circumferential rib  25   g , continuous or defined in segments and which projects over the upper end  13  of the tubular body  10 , so as to be loosely and telescopically fitted externally or internally to the lower end  11  of another tubular body  10  stacked over said tubular body  10 .  
      In case the upper circumferential rib  25   g  presents a diameter that is smaller than the lower end  11  of the tubular body  10 , it will be fitted inside a circumferential recess  12   a  provided in the bottom wall  12 , internally to the lower end  11  of another tubular body  10  stacked over said tubular body  10 .  
      While the invention has been described in relation to a can embodiment presenting only one constructive form, it should be understood that alterations could be made, without departing from the scope of protection defined in the appended claims.