Hemming apparatus

Abstract

A lower platen is provided with a hem punch and a slide cam. The hem punch is floating-supported to the slide cam. An upper platen is provided with a hem punch driver cam and a liner. The hem punch driver cam is used to change the hem punch to a pre-hemming position and to a final hemming position. The liner applies a processing load to the hem punch being in the final hemming position. By moving the hem punch to which the processing load is applied from the liner, a final hemming part of the hem punch is pressed against a bent portion of the workpiece.

1 . A hemming apparatus for hemming a bent portion of a workpiece previously formed to rise from the body of the workpiece, the hemming apparatus comprising:
 a first platen including a hemming die for supporting the workpiece, a hem punch including a pre-hemming part and a final hemming part both for hemming the bent portion of the workpiece, a slide cam to which the hem punch is attached, a slide cam guide mechanism for guiding the slide cam in a direction to laterally move the slide cam towards and away from the bent portion, and a hem punch support mechanism for floating-supporting the hem punch to the slide cam; and   a second platen disposed to face the first platen and including a hem punch driver cam engageable with the slide cam and a load application mechanism for applying a processing load to the hem punch, the hem punch driver cam being configured to move the slide cam to change the hem punch to a pre-hemming position at which the pre-hemming part is pressed against the bent portion of the workpiece and to a final hemming position at which the final hemming part faces the bent portion of the workpiece, the load application mechanism being configured to apply a processing load to the hem punch being in the final hemming position.   
   
   
       2 . The hemming apparatus of  claim 1 , wherein the hem punch support mechanism includes a hem punch urging member urging the hem punch opposite to a direction in which the processing load is applied. 
   
   
       3 . The hemming apparatus of  claim 1 , wherein
 the hemming apparatus further includes a workpiece holder for holding a held portion formed in the workpiece by pressing the workpiece holder against the held portion,   the workpiece holder includes a pad bearable against the held portion of the workpiece, a pad support mechanism for supporting the pad to the second platen and moving the pad in a direction towards and away from the held portion of the workpiece, and a pad driver cam disposed on the first platen and engageable with the pad support mechanism, and   the pad driver cam is configured to actuate the pad support mechanism to switch the pad between a position close to the held portion of the workpiece and a position away from the held portion.   
   
   
       4 . The hemming apparatus of  claim 3 , wherein the pad support mechanism includes a link connecting the pad to the second platen, and a pad urging member urging the pad in a direction away from the held portion of the workpiece. 
   
   
       5 . The hemming apparatus of  claim 3 , wherein
 the hem punch comprises a plurality of spaced-apart hem punches, and   the pad of the workpiece holder is disposed between each two adjacent said hem punches.