Adjustable die and punch for sheet material fastening machines

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 double-acting 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.

What is claimed is: 
     
       1. Punch and die apparatus for fastening overlying planar sheets of metal or other deformable material, said apparatus comprising: a. a press having longitudinally movable first and second rams supported on a rigid base;   b. a longitudinally extending pierce-and-forming punch rigidly mounted on said base, said punch having a free end face;   c. a cutting-and-forming die rigidly mounted on said first ram for movement therewith, said die having a longitudinally extending punch-receiving aperture into which said pierce-and-forming punch is receivable when said first ram is extended;   d. a flattening punch rigidly mounted on said second ram for movement therewith, said flattening punch being longitudinally slidably received in said punch-receiving aperture;   e. said flattening punch having an end face cooperable with said end face of said pierce-and-forming punch when said second ram is extended;   f. means for adjusting the spacing between the end faces of said flattening punch and pierce-and-forming punch when said second ram is extended; and   g. means for adjusting the phase relation between the times of extensions of said first and second rams.   
     
     
       2. Apparatus according to claim 1 characterized in that said means for adjusting said phase relation comprises means for adjusting the timing of said second ram. 
     
     
       3. Apparatus according to claim 2 characterized in that: a. said first and second rams are driven by a common shaft through first and second eccentrics;   b. said means for adjusting said phase relation comprises means for adjusting the angular position of the second eccentric on said common shaft.   
     
     
       4. Apparatus according to claim 2 characterized in that said means for adjusting the spacing between the end face of said punches comprises means for adjusting the position of said end face of said flattening punch. 
     
     
       5. Apparatus according to claim 3 characterized in that said means for adjusting the spacing between the end face of said punches comprises means for adjusting the position of said end face of said flattening punch. 
     
     
       6. Apparatus according to claim 1 characterized in that: a. said cutting-and-forming die includes a die holder and a hollow die carried by said die holder;   b. said die holder has a first set of fine external threads and a second set of heavy external threads;   c. first threaded means engage with said set of fine threads for supporting said die holder in said first ram against gravitational forces;   d. second threaded means engage with said set of heavy threads for taking the upward thrust imposed on said die during the fastening operation and directing said thrust to said first ram along a path which bypasses and protects said fine threads from said thrust forces;   e. said second threaded means are adapted to permit rotational movement of said holder in said first threaded means to allow for fine adjustment of the free end of said die.   
     
     
       7. Apparatus according to claim 6 characterized in that said first ram includes a lower neck portion which receives said die holder. 
     
     
       8. Apparatus according to claim 7 characterized in that said second threaded means includes an internally-threaded clamping ring which when rotated into a locking position abuts against the neck portion of said first ram. 
     
     
       9. Apparatus according to claim 6 characterized in that: a. said flattening punch has an elongated shank in the aligned center bores of said die holder and die;   b. drive means are provided which include first and second eccentric cranks for said first and second rams;   c. said second eccentric crank for said second ram is out of phase in the delayed direction with said first crank which drives said first ram;   d. the phase relationship between said first crank and said second crank is such that when said flattening punch reaches the downward limit of its stroke said die has been raised above its downward limit to an extent sufficient to uncover only the lower most of the overlying displaced sections of metal sheets.   
     
     
       10. Punch and die apparatus for fastening overlying planar sheets of metal or other deformable material, said apparatus comprising: a. a press having reciprocatingly movable first and second rams;   b. a pierce-and-forming punch and a cutting-and-forming die opposingly positioned, one of which is mounted on said first ram for movement therewith;   c. said die having a longitudinally extending aperture into which the free end face of said pierce-and-forming punch is received when said first ram is extended;   d. a flattening punch mounted on said second ram for movement therewith, said flattening punch being slidably received in said punch-receiving aperture of said die;   e. said flattening punch having an end face which becomes cooperable with the end face of said piercing-and-forming punch when said second ram is extended to an extent sufficient to bring the end free of said flattening punch beyond the end of said die aperture and outside said die;   f. means for adjusting the spacing between the end faces of said flattening punch and pierce-and-forming punch when said second ram is extended; and   g. means for adjusting the phase relation between the times of extensions of said first and second rams.   
     
     
       11. Apparatus according to claim 10 wherein said die is mounted on said first ram for movement therewith. 
     
     
       12. Apparatus for locking together overlying sheets of deformable material, said apparatus comprising: a. means for piercing first and second overlying sheets discontinuously along a boundary line defining an area for 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   b. means for 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. .Iadd.   
     
     
       13.  Spot clinch tool for forming a spot clinch joint by lancing and swaging two or more materials together using one complete stroke of a power source in a single station, said power source having a power stroke and a retract stroke, said tool utilizing an anvil, die and punch means for moving one of said punch and anvil while maintaining the other stationary during said complete stroke of said power source,   means for moving one of said punch and anvil toward the other during a first part of said power stroke,   means for piercing said materials with said punch and die to lance them during a second part of said power stroke,   means for holding the die in a first position spaced from the anvil during both said first and second parts of said power stroke,   means for moving the die to a second position in respect to said anvil during a third part of said power stroke,   means for swaging the lanced portions of said materials with said punch and anvil during a fourth and final part of said power stroke,   means for maintaining the die and the anvil in said second position during said fourth and final part of said power stroke and during a first part of said retract stroke, and   means for moving said die relative to said anvil from said second position to said first position during a second and final part of said retract stroke. .Iaddend. .Iadd.   
     
     
       14.  Spot clinch method for forming a spot clinch joint by lancing and swaging two or more materials together using one complete stroke of a power source in a single station, said power source having a power stroke and a retract stroke, said method utilizing an anvil, die and punch, said method comprising moving one of said punch and anvil while maintaining the other stationary during said complete stroke of said power source,   moving said one of said punch and anvil toward the other during a first part of said power stroke,   lancing said materials by piercing them with said punch and die during a second part of said power stroke,   holding the die in a first position spaced from the anvil during both said first and second parts of said power stroke,   moving the die to a second position in respect to said anvil during a third part of said power stroke,   swaging the lanced portion of said materials during a fourth and final part of said power stroke,   maintaining the die and the anvil in said second position during said fourth and final part of said power stroke and during a first part of said retract stroke,   and moving said die relative to said anvil from said second position to said first position during a second and final part of said retract stroke. .Iaddend.