Thread Forming Apparatus And Associated Method

Abstract

A thread forming apparatus includes an outer ring having a plurality of projections disposed around an inner periphery thereof, the outer ring being structured to remain stationary, an inner ring including a plurality of recesses disposed around an outer periphery thereof, the inner ring being structured to be moved radially toward a sidewall of a can body positioned between the outer ring and the inner ring and rotated against the sidewall and the projections. The rotation against the can sidewall and the projections causes can material to flow into the recesses and form a plurality of threads around the inner circumference of the can body. An actuator is coupled to the outer ring and the inner ring and structured to hold the outer ring stationary and the inner ring radially and rotate the inner ring against the sidewall.

What is claimed is: 
     
         1 . A thread forming apparatus structured to form a plurality of threads around a circumference of a can body having a base and a sidewall extending from the base, the thread forming apparatus comprising:
 an outer ring including a plurality of projections disposed around an inner periphery of the outer ring, the outer ring being structured to remain stationary;   an inner ring including a plurality of recesses disposed around an outer periphery of the inner ring; and   an actuator coupled to the outer ring and the inner ring,   wherein when the sidewall of a can body is positioned between the inner ring and the outer ring the inner ring is structured to be moved radially toward the sidewall of the can body and rotated against the sidewall and the projections, the rotation against the can sidewall and the projections causing can material to flow into the recesses and form the plurality of threads around the inner circumference of the can body, and   wherein the actuator is structured to hold the outer ring stationary and move radially and rotate the inner ring against the can sidewall.   
     
     
         2 . The apparatus of  claim 1 , wherein when the sidewall of a can body is positioned between the inner ring and the outer ring, upon actuation the inner ring is moved outward and starts to be rotated against the inner periphery of the outer ring, the rotation causing the inner ring to press against the can sidewall and projection against the can sidewall and a projection, and wherein the pressing causes the can material to flow into a recess and form an internal thread on the can sidewall. 
     
     
         3 . The apparatus of  claim 2 , wherein upon completion of formation of the internal thread, the inner ring rolls away from the internal thread and continues to be rotated to form remaining internal threads one by one. 
     
     
         4 . The apparatus of  claim 3 , wherein upon completion of forming the remaining internal threads, the can body is released from the apparatus. 
     
     
         5 . The apparatus of  claim 4 , wherein the inner ring and the outer ring is structured to keep the can body stationary until the release. 
     
     
         6 . A thread forming apparatus structured to form a plurality of threads around a circumference of a can body having a base and a sidewall extending from the base, the thread forming apparatus comprising:
 an outer ring including a plurality of recesses disposed around an inner periphery of the outer ring, the outer ring being structured to be moved radially toward the can body such that one end of each recess contacts the outer circumference of the can body;   an inner ring including a plurality of projections disposed around an outer periphery of the inner ring, the inner ring being structured to be moved among the recesses in a pattern and press the projections into the can sidewall and respective recesses, pressing the projections into the respective recesses causing can material to flow into the respective recesses and form the threads around the outer circumference of the can body; and   an actuator coupled to the outer ring and the inner ring and structured to move radially the outer ring and the inner ring to form the plurality of threads in the pattern.   
     
     
         7 . The thread forming apparatus of  claim 6 , wherein the pattern is of a star shape. 
     
     
         8 . The thread forming apparatus of  claim 6 , wherein the plurality of recesses are disposed equidistant around the inner periphery of the outer ring. 
     
     
         9 . The thread forming apparatus of  claim 6 , wherein the plurality of projections are disposed equidistant around the outer periphery of the inner ring.