Apparatus and method for forming a clinch joint

Abstract

An apparatus for forming a clinch joint in overlapping sheets of deformable material and the related method is disclosed. The apparatus includes a die assembly which cooperates with a punch. The die assembly includes an elongated mandrel having an anvil projecting axially from one end for deforming the sheets of material squeezed between the anvil and the punch. The mandrel is larger than the anvil to define a shoulder thereabout generally perpendicular to the die axis. An expandable die button is coaxially aligned upon the mandrel and is provided with a base ring encircling the mandrel and a plurality of die segments. The die segments each have a head portion and a leaf portion extending between the head and the base ring. The head portions collectively provide a die face surrounding the anvil to support the sheet of material and to define a central recess into which the punch can draw the material forming the joint, each head portion having a land parallel to and cooperating with the mandrel shoulder to transmit the axial load exerted thereon into the mandrel without transmitting axial load through the leaf portions. Alternative embodiments of the apparatus are disclosed for forming leak proof and lance type clinch joints.

Dependencies are inferred from the claim text.