Keywords
Citation
(2000), "Joint formed by punch", Assembly Automation, Vol. 20 No. 2. https://doi.org/10.1108/aa.2000.03320bad.008
Publisher
:Emerald Group Publishing Limited
Copyright © 2000, MCB UP Limited
Joint formed by punch
Joint formed by punch
Keywords: Assembly, Joining
Applicant: BTM Corp. (US)Patent number US5984563Publication date: 16 November 1999Title: Apparatus for joining sheet material and joint formed therein
Conventional leakproof joints have seen tremendous commercial success for use in applications such as microwave ovens and aluminium automobile bodies. They consist of two or more sheets of material having a button or joint formed by a uniformly cylindrical punch forcibly pushing a punch side sheet of material into interlocking engagement with a die side sheet of material. In the present invention, an improved apparatus for joining sheet material provides a stepped punch. This serves to strengthen a joint between two or more sheets of material by creating a stepped segment in at least one of these sheets of material. During formation of this stepped segment, material is forcibly displaced toward another segment of material that is outwardly expanded to interlock with the adjacent sheet of material. The punch and joint achieve a surprisingly stronger leakproof joint. Furthermore, the joint has improved wall thickness that is more resistant to fracture as compared with conventional leakproof joints. The punch, joint and method thus reduce scrap during the joint forming process.