Abstract

A draw punch (10) especially adapted to form holes in sheet metal material (16) includes an elongate draw rod 26 formed with a partially threaded, major diameter section (28) engageable with the stem (18) of an actuator (12). The draw rod (26) also includes a partially threaded minor diameter section (30) insertable within a pilot hole (24) formed in the sheet metal wall (16). A tapered pilot shoulder (32) interconnects the draw rod major and minor diameter sections (28) and (30). A male punch (34) is slidable over the draw rod major diameter section (28) to abut against the actuator (12). A female die (44) includes a disk-shaped backing member (46) slidably engageable over the draw rod minor diameter section (30) and a cylindrical cutting member (52) disposed between the backing member (46) and the punch (34). The cylindrical member (52) has a smaller diameter bore portion (56) adjacent the punch (34) to form a cutting edge with the adjacent end of the punch (34) and a larger diameter clearance bore portion (54) adjacent the die backing member (46). With the punch (34) and the die (44) disposed on opposite sides of the sheet metal wall (16), operation of the actuating means (12) forces the punch and die towards each other to sever an annularly shaped slug (60) from the wall (16).

Other References

• Exhibit 1--Catalog distributed by Enerpac (pp. 21, 22 and 23)
• Exhibit 2--Catalog distributed by Greenlee Tool Div. of Ex-Cel-O Corp. (pp. 70 and 71)