Container with seamed closure and method and apparatus for its manufacture

Abstract

The invention relates to a container comprising a diaphragm ( 40 ) secured to a can body ( 1 ) by means of a clamped seal. In particular, a method and apparatus for making the container are disclosed.

1 . A method of forming a container, the method comprising the following steps:
 i. radially expanding the sidewall of a tubular can body at an end of the can body to define a circumferential radially-expanded region in the sidewall adjacent the end of the can body;   ii. applying a first axial load to the can body whilst using means adapted to limit radial growth of the end of the can body so that all or part of the circumferential radially-expanded region partially axially collapses to form an outwardly-directed open annular bead;   iii. locating a diaphragm relative to the can body so that a peripheral annular portion of the diaphragm locates between opposing surfaces of the open annular bead; and   iv. applying a second axial load to the can body to fully axially collapse the bead to thereby clamp the peripheral annular portion of the diaphragm between the opposing surfaces of the bead and close the end of the can body.   
     
     
         2 . A method as claimed in  claim 1 , wherein steps i & ii are performed substantially simultaneously. 
     
     
         3 . A method as claimed in  claim 2 , wherein steps i and ii comprise inserting a flared die within the end of the can body to apply both radial and axial loads to the can body, the flared die terminating in a generally radially-extending end face, a limit ring situated adjacent the end face, the limit ring having a generally axially-extending wall to thereby limit radial growth of the end of the can body. 
     
     
         4 . A method as claimed in  claim 1 , wherein steps i and ii comprise inserting a flared die within the end of the can body to apply both radial and axial loads to the can body, the flared die and/or the limit ring defining an outwardly-curled end face, such that insertion of the flared die into the can body causes the free edge at the end of the can body to propagate along the surface of the outwardly-curled end face to form a curl, formation of the curl limiting further propagation of the free edge such that further insertion of the flared die induces the partial axial collapse of all or part of the circumferential radially-expanded region to form the outwardly-directed open annular bead. 
     
     
         5 . A method as claimed in  claim 4 , wherein during or subsequent to step iv, the curl is substantially flattened against the external surface of the collapsed bead to define a double thickness of metal above and adjacent the external surface of the collapsed bead. 
     
     
         6 . A method as claimed in  claim 1 , the method adapted during step ii to leave a portion of the sidewall of the can body extending between the partly collapsed outwardly-directed open annular bead and the free edge at the end of the can body, wherein simultaneously with or subsequent to step iv the portion is deformed to lie adjacent the exterior surface of the collapsed bead such that the free edge is outwardly-directed. 
     
     
         7 . A method as claimed in  claim 1 , the method adapted during step ii to leave a portion of the sidewall of the can body extending between the partly collapsed outwardly-directed open annular bead and the free edge at the end of the can body, wherein simultaneously with or subsequent to step iv the portion is wrapped around the periphery of the exterior surface of the collapsed bead so that the free edge is directed inwardly towards the can body sidewall. 
     
     
         8 . A method as claimed in  claim 1 , the method adapted during step ii to leave a portion of the sidewall of the can body extending between the partly collapsed outwardly-directed open annular bead and the free edge at the end of the can body, the portion comprising an inner region and an outer region, the inner region extending between the bead and the outer region, the outer region terminating at the free edge, wherein simultaneously with or subsequent to step iv the outer region is folded over the inner region, the combination of inner and outer regions then deformed such that the outer region is sandwiched between the inner region and the exterior surface of the collapsed bead to form a double thickness of metal above and adjacent the external surface of the collapsed bead. 
     
     
         9 . A method as claimed in  claim 1 , further comprising applying an upwards load to the underside of the fully collapsed bead to compress and tighten the clamped seal. 
     
     
         10 . A method as claimed in  claim 9 , wherein the sidewall of the can body is radially supported at the end of the can body during application of the upwards load to the underside of the fully collapsed bead. 
     
     
         11 . A method as claimed in  claim 1 , wherein the peripheral annular portion of the diaphragm as located between the opposing surfaces of the open annular bead during step iii comprises an upturned peripheral annular region, with the application of the second axial load during step iv acting to fold over the upturned peripheral annular region to thereby clamp a double thickness of diaphragm material between the opposing surfaces of the collapsed bead. 
     
     
         12 . An apparatus for forming a container, the apparatus having:
 i. a radial load member for radially expanding the sidewall at an end of a tubular metal can body to define a circumferential radially-expanded region in the sidewall adjacent the end of the can body;   ii. a first axial load member for applying a first axial load to the can body, plus a limit ring adapted to limit radial growth of the end of the can body such that during application of the first axial load the circumferential radially-expanded region partially axially collapses to form an outwardly-directed open annular bead;   iii. means for locating a peripheral annular portion of a diaphragm between opposing surfaces of the open annular bead;   iv. a second axial load member for applying a second axial load to the can body to fully axially collapse the bead to thereby clamp the peripheral annular portion of the diaphragm between the opposing surfaces of the bead and close the end of the can body.   
     
     
         13 . An apparatus as claimed in  claim 12 , comprising a flared die, the flared die acting as both the radial load member and first axial load member, the flared die terminating in a generally radially-extending end face, wherein the limit ring is situated adjacent the end face, the limit ring having a generally axially-extending wall to thereby limit radial growth of the end of the can body. 
     
     
         14 . An apparatus as claimed in  claim 12 , comprising a flared die, the flared die acting as both the radial load member and first axial load member, the flared die and/or the limit ring defining an outwardly-curled end face, such that insertion of the flared die into the can body causes the free edge at the end of the can body to propagate along the surface of the outwardly-curled end face to form a curl. 
     
     
         15 . An apparatus as claimed in  claim 13 , wherein the flared die and the limit ring are integrally formed. 
     
     
         16 . A container resulting from the method of  claim 1 .