Abstract A method and apparatus for joining two or more sheets of metal together and the composite metal blank and mechanical joint produced thereby. A punch and die apparatus is employed wherein a slug is extruded from a first sheet and embedded in a hole provided in a second sheet by the punching action of the slug. The punch never contacts the die itself and the resulting joint is between the slug from the first sheet and the second sheet in which it is embedded. The slug formed from the second sheet is sheared from the composite. By performing this operation in opposing corners of the two sheets, the sheets are secured together so as to prevent relative motion between them. The invention is particularly applicable to the formation of composite metal blanks having a pattern of stop-weld material sandwiched between the sheets.
A process of forming a joint between at least two sheets of metal, comprising the steps of: A. superimposing at least one first sheet of metal upon at least one second sheet of metal; B. forming a first slug of metal from a portion of said first superimposed sheet by extruding said first slug from said first sheet by the action of a punch, said punch having a radius formed about its leading edge, said first slug remaining connected to said first sheet by a continuous web portion. C. forming a second slug of metal from a portion of said second superimposed sheet, said second slug of metal being extruded from said second sheet by the punching action of said first slug, said second slug remaining connected to said second sheet by a web portion; D. embedding said first slug in said at least one second sheet at said portion of said second sheet from which said second slug has been formed so as to form a tight mechanical interfit, said first slug remaining connected to said first sheet by said continuous web portion, said first slug not extending out of said second sheet; and then E. shearing said second slug from said at least one second sheet.
Claim 2
Dependent Claim
208 words
A process of forming a joint between at least two sheets of metal, comprising the steps of: A. superimposing at least one first sheet of metal upon at least one second sheet of metal; B. forming a first slug of metal from a portion of said first superimposed sheet by extruding said first slug from said first sheet by the action of a punch, said punch having a radius formed about its leading edge, said first slug remaining connected to said first sheet by a continuous web portion. C. forming a second slug of metal from a portion of said second superimposed sheet, said second slug of metal being extruded from said second sheet by the punching action of said first slug, said second slug remaining connected to said second sheet by a web portion; D. embedding said first slug in said at least one second sheet at said portion of said second sheet from which said second slug has been formed so as to form a tight mechanical interfit, said first slug remaining connected to said first sheet by said continuous web portion, said first slug not extending out of said second sheet; and then E. shearing said second slug from said at least one second sheet.
Claim 3
Dependent Claim
35 words
A process as in claim 1 wherein a plurality of said joints are formed between said sheets of metal by repeating steps B, C, D and E for each of said plurality of said joints.
Claim 4
Dependent Claim
31 words
A process as in claim 2 wherein said sheets of metal comprise at least one metal selected from the group consisting of copper, copper base alloys, aluminum and aluminum base alloys.