Mechanical joining by clinch process involves punch and pressure pad and top and bottom stops to control pad movement and upset material neck region.

摘要

Before, during or immediately after the start of the clinching process the presure pad (9) is brought into active contact with the join part (4b) on the female die side and is thus to upset both parts (4a,4b) so the part (4a) on the punch side gains a thickened neck (6) due to the reduced ironing and in this way further material from both parts (4a,4b) is forced out of the eventual base area into the neck region (6) and the undercut region (7). The punch movement is overlain by a linear tumbling movement by the pad (9) at lower speed so pad reaches the bottom stop (11) directly at process end or shortly before this. Equipment comprises active punch (1), die (3) and pressure pad (9) as well as a holder to pre-clamp the two parts (4a,4b). The presure pad is addressed to the two parts (4a,4b) and the movement of the pad towards upper stop (10) is limited by the provision of a bottom stop (11). Pad (9) movement is controlled by mechanical springs (12) or again a servo-hydraulically controlled short-stroke cylinder.