Hydroformed bottom expansion process and apparatus

Abstract

An apparatus, and associated process, expands a wall of an associated metal container. The apparatus includes a holder for retaining at least a portion of the metal container. A first tool has a first surface mounted for movement relative to the holder for selective advancement toward and dimensioned to engage at least a portion of the associated metal container. The first tool includes a seal so that fluid received in the associated metal container is pressurized and used to apply an expanding force to the associated metal container as the first tool advances therein. A bubble is formed in the bottom wall, and in a second station, the combination of fluid pressure and metal forming surfaces make the final configuration of the bottom wall.

It is claimed: 
     
         1 . An apparatus for expanding a wall of an associated metal container comprising:
 a holder for retaining at least a portion of the associated metal container;   a first tool having a first surface mounted for movement relative to the holder for selective advancement toward and dimensioned to engage at least a portion of the associated metal container, and the first tool including a seal so that fluid received in the associated metal container is pressurized and used to applying an expanding force to the associated metal container as the first tool advances therein.   
     
     
         2 . The apparatus of  claim 1  wherein the first tool includes a fluid passage that communicates with a relief valve that opens in response to a preselected fluid pressure level in the associated metal container. 
     
     
         3 . The apparatus of  claim 1  wherein the first tool has a first end dimensioned for receipt into an open end of the associated metal container. 
     
     
         4 . The apparatus of  claim 1  wherein the first tool includes first and second portions that move in unison until the first portion abuts against a surface of the associated metal container, and the second portion then moves relative to the first portion and compresses the fluid in the associated metal container. 
     
     
         5 . The apparatus of  claim 4  wherein the seal is interposed between the first and second portions of the first tool. 
     
     
         6 . The apparatus of  claim 1  wherein a seal is provided on an outer surface of the second tool in a second station that engages an inner wall surface of the associated metal container. 
     
     
         7 . The apparatus of  claim 1  wherein a first station includes the first tool dimensioned for receipt through an open end of the associated metal container, and the first tool includes a leading end that is configured for engagement with the associated metal container at a location adjacent a sidewall connection with a bottom wall of the associated metal container. 
     
     
         8 . The apparatus of  claim 7  wherein the first tool includes first and second portions that move in unison until the first portion abuts against a surface of the associated metal container, the second portion then moves relative to the first portion and compresses the fluid in the associated metal container, and the seal is interposed between the first and second portions of the first tool. 
     
     
         9 . The apparatus of  claim 7  wherein a second station includes a second tool having a seal provided on an outer surface thereof dimensioned for engagement with an inner surface of the associated metal container, and a metal forming surface that is configured to engage a bottom wall of the associated metal container whereby the bottom wall is expanded by a combination of fluid pressure and the metal forming surface. 
     
     
         10 . A process for expanding a wall of a metal container comprising:
 positioning at least a portion of the metal container in a holder;   providing a fluid in the metal container;   advancing a tool into an interior of the metal container to retain the metal container between the tool and holder; and   further advancing the tool into metal container to pressurize the fluid and thereby expand a bottom wall of the metal container.   
     
     
         11 . The process of  claim 10  further comprising using a first portion of the tool to initially engage the metal container with the holder. 
     
     
         12 . The process of  claim 11  further comprising allowing a second portion of the tool to move relative to the tool first portion after the initial engagement of the tool first portion with the metal container. 
     
     
         13 . The process of  claim 10  further comprising sealing an interior cavity of the metal container with a seal on the tool to use fluid pressure to expand the metal container wall. 
     
     
         14 . The process of  claim 10  further comprising using fluid pressure to form an outward bubble in a bottom wall of the container. 
     
     
         15 . The process of  claim 14  further comprising using a combination of fluid pressure and metal tool forming to form the bubble into a desired configuration. 
     
     
         16 . The process of  claim 15  wherein forming the bubble into a desired configuration includes sealing between the metal container and the tool. 
     
     
         17 . The process of  claim 10  wherein in a first station, first and second portions of a first tool are configured for movement relative to one another, the first portion engaging an interior surface of the metal container at an interface between a sidewall and bottom wall of the metal container to retain the metal container. 
     
     
         18 . The process of  claim 17  wherein in the first station, a second portion of the first tool moves relative to the first portion to pressurize the fluid in the metal container and form a bubble extending outwardly in the bottom wall of the metal container. 
     
     
         19 . The process of  claim 18  further comprising transferring the metal container with the bubble into a second station where a tool advances into the open end thereof, sealingly engaging an interior surface of the metal container and forming the bubble of the bottom wall into a desired configuration with a combination of fluid pressure and a metal forming surface. 
     
     
         20 . The process of  claims 10  further including providing a pressure relief valve to vent an interior cavity of the metal container if the pressure exceeds a predetermined level.