Abstract To fasten together two or more overlying sheets of metal or other material having plasticity or deformable properties by partially piercing and deforming sections of the sheets, a fixed pierce-and-forming punch is used in cooperation with a doubleacting press having two separately actuatable rams. For displacing sections of the overlying sheets, one of the rams carries a hollow cylindrical pierce-and-forming die the die cavity of which is vertically aligned with, and cooperates with, a fixed pierce-and-forming punch supported in the base. The other of the rams carries a flattening punch which is slidably movable within the central bore of the hollow cylindrical die. The pierce-and-forming die is supported by means which includes fine adjustment means so that the position of the die may be adjusted for different thicknesses of sheets to be fastened, and also for wear on the die and/or punch. The flattening punch is supported by phase adjustment means which permits the angular relationship between the flattening punch and the die to be adjusted for different thicknesses of sheets to be fastened. The latter adjustment is made such that the downwardly-moving flattening punch engages the upper displaced section or sections just after the lower displaced section is uncovered by the upwardly-moving cylindrical die, thereby to spread the lower displaced section while the upper section or sections are still constrained.
An interlocking joint fastening together overlying sheets of metal or other material having permanently deformable properties, said sheets including at least a first sheet and an overlying second sheet, said sheets having interior and opposed exterior surfaces, said overlying sheets having been pierced discontinuously along a boundary line defining a minor area, the material of said first and second sheets within said minor area having been displaced out of the respective planes of the majorarea material of said first and second sheets forming first and second overlying bridge portions, material of said first bridge portion being spread laterally over the exterior surface of the major-area material of said second sheet beyond the piercings therein, the improvement characterized by the material of said second bridge portion being confined within the limits defined by said piercings during the application of compressive force to the exterior surface of said second bridge portion, whereby said first bridge portion is spread laterally beyond the limits of said second bridge portion.
Claim 2
Dependent Claim
165 words
An interlocking joint fastening together overlying sheets of metal or other material having permanently deformable properties, said sheets including at least a first sheet and an overlying second sheet, said sheets having interior and opposed exterior surfaces, said overlying sheets having been pierced discontinuously along a boundary line defining a minor area, the material of said first and second sheets within said minor area having been displaced out of the respective planes of the majorarea material of said first and second sheets forming first and second overlying bridge portions, material of said first bridge portion being spread laterally over the exterior surface of the major-area material of said second sheet beyond the piercings therein, the improvement characterized by the material of said second bridge portion being confined within the limits defined by said piercings during the application of compressive force to the exterior surface of said second bridge portion, whereby said first bridge portion is spread laterally beyond the limits of said second bridge portion.