Push-in easy-opening closures

Abstract

This specification discloses an easy-opening closure for a can end which comprises an opening formed by partially severing a portion from the can end to leave the portion attached thereto by an integral neck, and a closure member formed from said severed portion and which is larger than said opening. The sheet metal adjacent the free edge of the opening is downwardly turned while the sheet metal adjacent the free edge of the closure member is upwardly turned, said free edges being in contact with or in close proximity to each other. A sealant is applied at least in the region of the free edges if required by the purpose for which the can end is to be used. The specification also discloses a method of forming such a closure comprising the steps of: forming an upwardly directed bulge in the sheet metal, thus stretching the sheet; partially severing a central portion of said bulge, to define an opening and said severed portion defining a closure member for said opening, and displacing the closure member downwardly so that its free edge is below the free edge of the opening; partially flattening the thus truncated bulge of sheet metal around said opening to reduce its size, and turning downwardly said free edge defining said opening; partially flattening the closure member to increase its size, and turning upwardly said free edge of the closure member, the free edge portion of said closure member being in contact with or in close proximity to said free edge defining said opening, and applying a sealant at least in the region of the free edges of the opening and the closure member to seal the closure if required by the purpose for which said container member is to be used.

We claim: 
     
       1. A method of forming an easy-opening.Iadd., push-in .Iaddend.closure in a sheet metal container member, said method comprising: forming a bulge in an area of the sheet metal container member,   at least partially severing a portion of the sheet metal in said area to provide a free edge, wherein at least a portion of said bulge lies substantially outside of said portion,   the free edge of the sheet metal from which said portion is at least partially severed defining an opening, and said severed portion defining a closure member for said opening, .Iadd.   wherein said bulge includes an approximately flat area of sheet metal that is generally parallel to the plane of the sheet metal surrounding said bulge, said severing being carried out substantially within said flat area.Iaddend.,     thereafter reducing the size of said opening by at least partly flattening said bulge, to place .[.at least a part of the free edge portion of said closure member and.]. the free edge defining said opening or the interior surface of the sheet metal adjacent said opening in overlapping contact or in overlapping close proximity .Iadd.over at least a part of the free edge portion of said closure member, .Iaddend.     whereby said container member having said easy-opening closure is suitable for use in forming a container for liquids.   
     
     
       2. Method as claimed in claim 1, wherein said portion of the sheet metal is only partially severed with at least one unsevered area connecting said closure member to the remainder of said sheet metal and serving as a hinge during the closure opening operation.  .[.3. Method as claimed in claim 2, wherein said bulge includes an approximately flat area of sheet metal that is generally parallel to the plane of the sheet metal surrounding said bulge, said severing being carried out substantially within said flat 
     
     
        area..]. 4. Method as claimed in claim .[.3.]. .Iadd.1.Iaddend., wherein 
     
     
        said sheet metal is steel. 5. Method as claimed in claim 4, wherein after said bulge is flattened, a sealant is applied to at least the region of 
     
     
        the free edges of said opening and said closure member. 6. Method as claimed in claim 4, wherein the container contents are below atmospheric 
     
     
        pressure. 7. Method as claimed in claim 4, wherein the container contents 
     
     
        are above atmospheric pressure. 8. Method as claimed in claim 2, wherein 
     
     
        said bulge is formed before said portion is severed. 9. Method as claimed in claim 8, wherein the size of said closure member is increased prior to 
     
     
        the application of said sealant. 10. Method as claimed in claim 9, wherein said closure member is bulged when severed, and thereafter the bulged 
     
     
        closure member is flattened to increase the size thereof. 11. Method as claimed in claim 2, wherein said free edge portion of said closure member has a plurality of segments, at least one of said segments overlying a surface of the sheet metal adjacent said opening, and at least one other of said segments overlying the opposite surface of the sheet metal 
     
     
        adjacent said opening. 12. .[.Method as claimed in claim 2.]. .Iadd.A method of forming an easy-opening closure in a sheet metal container member, said method comprising forming a bulge in an area of the sheet metal container member, at least partially severing a portion of the sheet metal in said area to provide a free edge wherein at least a portion of said bulge lies substantially outside of said portion, the free edge of the sheet metal from which said portion is at least partially severed defining an opening, and said severed portion defining a closure member for said opening, thereafter reducing the size of said opening by at least partly flattening said bulge to place at least a part of the free edge portion of said closure member and the free edge defining said opening or the interior surface of the sheet metal adjacent said opening in overlapping contact or in overlapping close proximity, whereby said container member having said easy-opening closure is suitable for use in forming a container for liquids, wherein said portion of the sheet metal is only partially severed with at least one unsevered area connecting said closure member to the remainder of said sheet metal and serving as a hinge during the closure opening operation.Iaddend. ; wherein said unsevered area is located in the bulged area of the sheet metal container member. 
     
     
            A method of forming an easy-opening closure in a container member of sheet metal comprising the following steps: 1. forming a bulge in the sheet metal, thus stretching the sheet;   2. partially or wholly severing a central portion of said bulge to provide a free edge, the free edge of said sheet metal from which said portion is severed defining an opening and said severed portion defining a closure member for said opening;   3. displacing the closure member in the opposite direction from said bulge so that its free edge is in a different plane than the free edge of the opening;   4. at least partially flattening the bulge of sheet metal around said opening to reduce its size and to place at least a part of the free edge portion of said closure member and said free edge defining said opening or the surface of the sheet metal adjacent said opening in overlapping contact or in overlapping close proximity, and   5. applying a sealant at least in the region of the free edges of the opening and the closure member to seal the closure if required by the purpose for which said container member is to be used, whereby said container member having said easy-opening closure is suitable for use in   
     
     
        forming a container for liquids. 14. Process as claimed in claim 13, wherein the free edge defining said opening is displaced in the direction 
     
     
        of the closure member displacement. 15. Method as claimed in claim 13, 
     
     
        wherein steps (1) and (2) are in a single operation. 16. Method as claimed in claim 13, wherein said bulge includes an approximately flat area of sheet metal that is generally parallel to the plane of the sheet metal surrounding said bulge, said severing being carried out substantially 
     
     
        within said flat area. 17. Method as claimed in claim 16, wherein said portion of the sheet metal is only partially severed with at least one unsevered area connecting said closure member to the remainder of said sheet metal and serving as a hinge during the closure opening operation. 
     
     
          . Method as claimed in claim 17, wherein said sheet metal is steel. 19. Method as claimed in claim 13, wherein the closure member is bulged when severed and thereafter the bulged closure member is at least 
     
     
        partially flattened to increase its size. 20. A method of forming an easy-opening closure in a sheet metal container member, the steps comprising: forming a bulge in an area of the member to displace metal in said area generally normally on the sheet;   at least partially severing a portion of the displaced sheet metal inwardly of the periphery thereof to provide a free edge of displaced metal outwardly of the severed portion at least partially defining an opening, with said severed portion defining a closure member for said opening;   .Iadd.wherein said bulge includes an approximately flat area of sheet metal that is generally parallel to the plane of the sheet metal surrounding said bulge, said severing being carried out substantially within said flat area.Iaddend.;   and reducing the size of said opening by at least partly flattening the said displaced metal defining said opening to move the marginal portion of the free edge and the marginal edge portion of the closure member into   
     
     
        overlapping relationship. 21. .[.Method as claimed in claim 2,.]. .Iadd.A method of forming an easy-opening closure in a sheet metal container member, said method comprising forming a bulge in an area of the sheet metal container member, at least partially severing a portion of the sheet metal in said area to provide a free edge wherein at least a portion of said bulge lies substantially outside of said portion, the free edge of the sheet metal from which said portion is at least partially severed defining an opening, and said severed portion defining a closure member for said opening, thereafter reducing the size of said opening by at least partly flattening said bulge to place at least a part of the free edge portion of said closure member and the free edge defining said opening or the interior surface of the sheet metal adjacent said opening in overlapping contact or in overlapping close proximity, whereby said container member having said easy-opening closure is suitable for use in forming a container for liquids, wherein said portion of the sheet metal is only partially severed with at least one unsevered area connecting said closure member to the remainder of said sheet metal and serving as a hinge during the closure opening operation .Iaddend.wherein the free edge defining said opening is displaced towards the free edge portion of the closure member, whereby the easy-opening closure presents a smooth opening periphery to an opener's finger.