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.
A method of locking together overlying sheets of deformable material, said method comprising: a. piercing first and second overlying sheets discontinuously along a boundary line defining an area; b. displacing the material of said first and second sheets within said area out of the planes of the non-displaced first and second sheet material until the exterior surface of the Displaced first sheet material is just beyond the plane of the exterior surface of the non-displaced second sheet material; and c. compressing together the displaced material of said first and second sheets while confining the displaced material of the second sheet to limit its outward spread and to spread outwardly the displaced first sheet material over the outer surface of the non-displaced second sheet material beyond the edges of the piercings therein.
Claim 2
Independent Claim
131 words
A method of locking together overlying sheets of deformable material, said method comprising: a. piercing first and second overlying sheets discontinuously along a boundary line defining an area; b. displacing the material of said first and second sheets within said area out of the planes of the non-displaced first and second sheet material until the exterior surface of the Displaced first sheet material is just beyond the plane of the exterior surface of the non-displaced second sheet material; and c. compressing together the displaced material of said first and second sheets while confining the displaced material of the second sheet to limit its outward spread and to spread outwardly the displaced first sheet material over the outer surface of the non-displaced second sheet material beyond the edges of the piercings therein.