Patent ID: 6742235
Filing Date: 2004-06-01
Classification: B21J,Y10T

Abstract:
A method for inserting a fastener into sheet material comprising inserting the fastener into at least one sheet without full penetration such that a deformed end of the fastener remains encapsulated by an upset annulus of the sheet material, the sheet material being disposed between a nose and a die of the fastening apparatus and the fastener being inserted into the sheet material by means of a plunger that is reciprocal relative to the nose, characterized in that, during a first stage of fastener insertion there is no significant clamping force so that the sheet material around the fastener insertion location is free to be displaced without significant constraint towards the fastener by virtue of its insertion, and thereafter during a second stage (being after said first stage) of fastener insertion a clamping force of sufficient magnitude is applied between the nose and the die in the region around fastener insertion location so as substantially to prevent flow of displaced sheet material away from the fastener.