Thread forming apparatus and associated method

Abstract

A thread forming apparatus includes a punch assembly having a punch cam and a punch. The punch includes a body having a first end engaged with the punch cam and a second end having a projection moved radially in response to engagement with the punch cam. The apparatus further includes a die assembly adjacent the punch assembly and defining a clearance therebetween to receive a portion of a sidewall of a can body. The die assembly includes a die cam and a die including a top portion having a die recess and a bottom portion engaged with the die cam, the die being moved radially in response to engagement with the die cam. The projection is structured to deform the portion of the sidewall of the can body into the die recess in a manner which forms the thread.

What is claimed is: 
     
         1 . A thread forming apparatus structured to form one or more threads on a can body having a base and a can sidewall extending from the base, the thread forming apparatus comprising:
 a punch assembly comprising:
 a punch cam; and 
 a punch comprising:
 a punch body having a first end and an opposite second end, the first end engaged with the punch cam; and 
 a punch projection disposed at the second end of the punch body, the punch being structured to move radially in response to engagement with the punch cam; and 
 
   a die assembly disposed adjacent to the punch assembly, the die assembly and the punch assembly defining a clearance therebetween structured to receive a portion of the sidewall of the can body, the die assembly comprising:
 a die cam structured to move axially parallel to the central axis; and 
 a die including:
 a top portion having a die recess; and 
 a bottom portion engaged with the die cam, the die being structured to move radially in response to axial movement of the die cam, 
 
   wherein the punch projection is structured to deform the portion of the sidewall of the can body into the die recess in a manner which forms the thread.   
     
     
         2 . The apparatus of  claim 1 , further comprising a number of actuators coupled to the punch cam and the die cam. 
     
     
         3 . The apparatus of  claim 2 , wherein the number of actuators are structured to axially move the punch cam and the die cam. 
     
     
         4 . The apparatus of  claim 1 , wherein the die further comprises a die guide structured to provide a linear guide to the die. 
     
     
         5 . The apparatus of  claim 1 , wherein the punch further comprises a punch guide engaged with the punch body and structured to constrain movement of the punch body to linear motion. 
     
     
         6 . The apparatus of  claim 1 , wherein the punch comprises a punch cam follower disposed at the first end of the punch body and engaged with the punch cam. 
     
     
         7 . The apparatus of  claim 1 , wherein the punch cam is structured to slide axially parallel to a central axis of the can body. 
     
     
         8 . The apparatus of  claim 1 , wherein to position the punch assembly and the die assembly for forming an internal thread on the can body, the punch cam is axially moved such that the punch projection is adjacent the sidewall of the can and the die cam is axially moved such that the recess is adjacent sidewall of the can opposite the punch projection. 
     
     
         9 . The apparatus of  claim 1 , wherein to form an internal thread, the punch cam is moved axially toward the base of the can body such that the punch projection is pressed radially toward the can sidewall and into the recess, thus forming the internal thread. 
     
     
         10 . The apparatus of  claim 1 , wherein to release the can body, both the punch cam and the die cam are moved axially away from the base of the can body such that the punch projection and the recess move away from the can sidewall and the newly formed internal thread. 
     
     
         11 . A method of forming one or more threads on a can body having a base and a sidewall extending from the base, the method comprising:
 disposing a portion of the sidewall of the can body in a clearance between a punch projection and a die recess of a die;   moving the punch projection and the die recess toward the portion of the sidewall of the can body so as to form a thread in the portion of the can body in the die recess about the punch projection; and   moving the punch projection and the die recess away from the portion of the sidewall of the can body so as to release the thread from the die recess and the punch projection.   
     
     
         12 . The method of  claim 11 , further comprising removing the portion of the sidewall from the clearance. 
     
     
         13 . The method of  claim 11 , further comprising:
 rotating the can body about a central longitudinal axis thereof so as to dispose a second portion of the sidewall of the can body in the clearance between the punch projection and the die recess of the die;   moving the punch projection and the die recess toward the second portion of the sidewall of the can body so as to form a thread in the second portion of the can body in the die recess about the punch projection; and   moving the punch projection and the die recess away from the second portion of the sidewall of the can body so as to release the thread from the die recess and the punch projection.   
     
     
         14 . The method of  claim 11 , further comprising:
 disposing a second portion of the sidewall of the can body in a clearance between a second punch projection and a die recess of a second die;   moving the second punch projection and the die recess of the second die toward the second portion of the sidewall of the can body so as to form a second thread in the second portion of the can body in the die recess of the second die about the second punch projection; and   moving the second punch projection and the die recess of the second die away from the second portion of the sidewall of the can body so as to release the second thread from the die recess of the second die and the second punch projection.