| 摘要 |
<p>Manufacture for recessed rivets comprises (1). The wire or rod shaped cut-off blank is introduced into the dia. contacting a punch in its bore. (2) The head of the rivet is partially formed by a blow delivered by a punch in front of the die pressing the constrained end of blank lightly against the inner punch. Pref. this is followed by a second blow from the front when the head is formed in its final form, after which, with the rivet still held in place by the punch in front, the punch in the rear is blown inwards resulting in forming of the recess whence the finished rivet may be ejected at the front after retraction of the head punch. The process is simple and uses a minimal number of process steps.</p> |
