Fastening apparatus

摘要

A fastening apparatus includes a spring (27) operable to inwardly bias a pair of die blades (29) toward an anvil (23). The anvil and die blades act in conjunction with a punch (35) to form either an interlocking lanced joint or a contiguous, leakproof, inverted mushroom-shaped joint. The anvil (23) has a flat external face and the spring (27) includes a pair of spring arms (41) joined by a bridge (43). The spring (27) extends around an external surface of a die body (25).