Can base forming

Abstract

An apparatus for forming a base profile on a metal container carried on a punch moving along an axis. The apparatus comprises a die for forming the base profile on the container and a resilient support for holding the die in a resting position substantially along said axis whilst allowing the die to be deflectable perpendicular to said axis and providing a restoring force to return the die to the resting position.

1 - 15 . 
     
     
         16 . An apparatus for forming a base profile on a metal container carried on a punch moving along an axis, the apparatus comprising:
 a die for forming the base profile on the container;   a hold down ring surrounding the die and slidable thereon against a restoring force along said axis to contact a container base ahead of the die; and   a resilient support for holding the hold down ring in a resting position surrounding the die whilst allowing the hold down ring to be deflectable perpendicular to said axis and providing a restoring force perpendicular to said axis to return the hold down ring to the resting position.   
     
     
         17 . The apparatus according to  claim 16 , wherein the hold down ring is deflectable perpendicular to said axis by more than 100 μm and preferably by more than 500 μm. 
     
     
         18 . The apparatus according to  claim 16 , wherein said die is not moveable by the punch. 
     
     
         19 . The apparatus according to  claim 16 , further comprising one or more sensors for measuring deflection of the hold down ring perpendicular to said axis. 
     
     
         20 . The apparatus according to  claim 19 , wherein the one or more sensors are eddy current sensors. 
     
     
         21 . The apparatus according to  claim 20 , further comprising a housing surrounding the hold down ring and deflectable in conjunction with the hold down ring perpendicular to said axis, the eddy current sensor(s) being configured to measure deflection of the housing perpendicular to said axis. 
     
     
         22 . The apparatus according to  claim 21 , wherein the eddy current sensors comprise four eddy current sensors in a substantially equiangular arrangement with respect to the axis. 
     
     
         23 . A can bodymaker comprising the apparatus of  claim 16 . 
     
     
         24 . A method for forming a base profile on a metal container and comprising locating a container on a punch, using the punch to drive the container base, in an axial direction, against a hold down ring surrounding a die defining said base profile, the hold down ring being slidable on the die against a restoring force along said axis to contact the container base ahead of the die, wherein the hold down ring is deflectable upon impact of the container base against the hold down ring, perpendicular to said axial direction against a restoring force perpendicular to said axial direction. 
     
     
         25 . The method according to  claim 24 , further comprising measuring the deflection of the hold down ring perpendicular to said axis by the punch.