Can base reforming

Abstract

A method and apparatus for reforming the base profile of a can by using the difference in rotational speed of concentric shafts (A, B) to move a roller ( 5 ) radially into contact with the can base. A cam ( 10 ) is fixed to one (B) of the shafts and a pair of cam followers ( 12, 14 ) is mounted on a support block ( 6 ) which is connected to the other shaft (A) via linear bearings ( 7, 8 ). The support block also carries the reform roller and causes it to rotate around the can base.

1 . An apparatus for reforming the base profile of a can, the apparatus comprising: 
 a roller for forming a desired new profile on the can base; and    first and second concentric shafts, the first shaft rotating the roller relative to the can, and the second shaft actuating the roller to move radially to engage the can when there is a speed differential between the two shafts.    
     
     
         2 . An apparatus according to  claim 1 , further comprising a cam or an eccentric for actuating the roller to move radially.  
     
     
         3 . An apparatus according to  claim 2 , in which the shafts rotate in the same direction.  
     
     
         4 . An apparatus according to  claim 2  or  3 , in which the cam or eccentric is fixed to the second shaft and one or more cam followers are mounted on the first shaft.  
     
     
         5 . An apparatus according to  claim 4 , in which the cam follower or followers is/are mounted on the first shaft via linear bearings.  
     
     
         6 . An apparatus according to any one of  claims 1  to  5 , in which the apparatus is one of a plurality of base profile reforming apparatus each of which is fixed at stations around a rotatable turret machine.  
     
     
         7 . An apparatus according to  claim 6 , in which the first shaft rotates +/− an integer number of rotations relative to the second shaft in one machine rotation.  
     
     
         8 . A method of reshaping the base profile of a can, the method comprising: 
 providing a roller for forming a desired new profile on the can base;    providing first and second concentric shafts;    rotating the roller relative to the can by means of the first shaft;    actuating the roller to move radially to engage the can by driving the first and second shafts at different speeds.