Stock lifter for metal forming dies and method for making the same

2 A progressive die as set forth in claim 1, wherein:

• said spring unit aperture in said base plate includes an internal thread;
• and
• said spring unit base portion includes an external thread which mates with the internal thread of said spring unit aperture, such that rotation of said spring unit base relative to said base plate varies the axial position of said rod portion relative to said lifter bar to permit making stock lifters having different vertical lifts.

3 A progressive die as set forth in claim 2, including:

• a lock fastener mounted in said base plate, and engaging said base portion of said spring unit to retain said base portion in a selected rotational position in said base plate.

4 A progressive die as set forth in claim 3, including:

• fasteners extending through said third and fourth mounting apertures in said lifter bar, and connecting second ends of said guide shafts with said lifter bar;
• and
• stops positioned on the first ends of said guide shafts and having radially extending collars which selectively abut said base plate to limit reciprocation of said lifter bar.

5 A progressive die as set forth in claim 4, wherein:

• said fastener mechanism comprises an aperture extending completely through said base plate.

6 A progressive die as set forth in claim 5, including:

• at least two bushings, each having an outside surface and an inside surface shaped to closely receive one of said guide shafts therein;
• and wherein
• said first and second guide shaft apertures are shaped to closely receive the outside surface of an associated one of said bushings therein.

7 A progressive die as set forth in claim 6, wherein:

• said base plate has a predetermined length, width and thickness;
• and
• said base is cut to length from a bar of steel having a width and thickness substantially commensurate with the predetermined width and thickness of said base plate to minimize machining said base plate.

8 A progressive die as set forth in claim 7, wherein:

• said guide shafts are constructed from a hardened steel, such that said base plate need not be hardened after assembly of said stock lifter.

9 A progressive die as set forth in claim 8, wherein:

• said bar from which said base plate is cut is constructed from 4140 cold drawn steel.

10 A progressive die as set forth in claim 9, wherein:

• said die includes a lower die block with through apertures disposed directly below said first and second shaft mounting apertures to avoid machining said lower die block.

11 A progressive die as set forth in claim 10, including:

• bumpers mounted on said guide shafts adjacent said stops.

12 A progressive die as set forth in claim 11, including:

• at least one fastener extending through said fastener aperture, and detachably mounting said stock lifter on said lower die block.

13 A progressive die as set forth in claim 12, wherein:

• said stock lifter includes a stock guide connected with said lifter bar, and configured to guide the stock along said multiple stations of said metal forming die.

14 A progressive die as set forth in claim 13, wherein:

• said rod portion of said spring unit is detachably connected with said base portion, whereby different length rod portions can be mounted in said base portion to permit making stock lifters having different vertical lifts from said base plate, said lifter bar and said spring unit.

15 A progressive die as set forth in claim 14, wherein:

• said spring unit is gas pressure operated.

16 A progressive die as set forth in claim 15, wherein:

• said guide shaft fasteners comprise cap screws.

17 A progressive die as set forth in claim 16, wherein:

• said lifter bar includes a substantially flat lower surface;
• and
• said guide shafts include upper ends which abut the lower surface of said lifter bar.

18 A progressive die as set forth in claim 1, including:

• fasteners extending through said third and fourth mounting apertures in said lifter bar, and connecting second ends of said guide shafts with said lifter bar;
• and
• stops positioned on the first ends of said guide shafts and having radially extending collars which selectively abut said base plate to limit reciprocation of said lifter bar.

19 A progressive die as set forth in claim 1, including:

• at least two bushings, each having an outside surface and an inside surface shaped to closely receive one of said guide shafts therein;
• and wherein
• said first and second guide shaft apertures are shaped to closely receive the outside surface of an associated one of said bushings therein.

20 A progressive die as set forth in claim 1, wherein:

• said base plate has a predetermined length, width and thickness;
• and
• said base is cut to length from a bar of steel having a width and thickness substantially commensurate with the predetermined width and thickness of said base plate to minimize machining said base plate.

21 A progressive die as set forth in claim 1, wherein:

• said guide shafts are constructed from a hardened steel, such that said base plate need not be hardened after assembly of said stock lifter.

22 A progressive die as set forth in claim 1, wherein:

• said base plate is constructed from 4140 cold drawn steel.

23 A progressive die as set forth in claim 1, wherein:

• said die includes a lower die block with through apertures disposed directly below said first and second shaft mounting apertures to avoid machining said lower die block.

24 A progressive die as set forth in claim 1, wherein:

• said fastener mechanism comprises an aperture extending completely through said base plate.

25 A progressive die as set forth in claim 1, wherein:

• said stock lifter includes a stock guide connected with said lifter bar, and configured to guide the stock along said multiple stations of said metal forming die.

26 A progressive die as set forth in claim 1, wherein:

• said rod portion of said spring unit is detachably connected with said base portion, whereby different length rod portions can be mounted in said base portion to permit making stock lifters having different vertical lifts from said base plate, said lifter bar and said spring unit.

27 A progressive die as set forth in claim 1, wherein:

• said spring unit is gas pressure operated.

28 A progressive die as set forth in claim 1, wherein:

• said lifter bar includes a substantially flat lower surface;
• and
• said guide shafts include upper ends which abut the lower surface of said lifter bar.

30 A progressive die as set forth in claim 29, wherein:

• said spring unit aperture in said base modular plate includes an internal thread;
• and
• said spring unit base portion includes an external thread which mates with the internal thread of said spring unit aperture, such that rotation of said spring unit base relative to said modular base plate varies the axial position of said rod portion relative to said modular lifter bar to permit making modular stock lifter assemblies having different vertical lifts.

32 A progressive die as set forth in claim 31, wherein:

• said spring unit aperture includes an internal thread;
• and
• said spring unit base portion includes an external thread which mates with the internal thread of said spring unit aperture, such that rotation of said spring unit base varies the axial position of said rod portion relative to said lifter bar to permit making stock lifters having different vertical lifts.

34 A progressive die as set forth in claim 33, wherein:

• said spring unit aperture in said base plate includes an internal thread;
• and
• said spring unit base portion includes an external thread which mates with the internal thread of said spring unit aperture, such that rotation of said spring unit base relative to said base plate varies the axial position of said rod portion relative to said lifter bar to permit making stock lifters having different vertical lifts.

35 A progressive die as set forth in claim 34, including:

• fasteners extending through said third and fourth mounting apertures in said lifter bar, and connecting second ends of said guide shafts with said lifter bar;
• and
• stops positioned on the first ends of said guide shafts and having radially extending collars which selectively abut said base plate to limit reciprocation of said lifter bar.

36 A progressive die as set forth in claim 35, including:

• at least two bushings, each having an outside surface and an inside surface shaped to closely receive one of said guide shafts therein;
• and wherein
• said first and second guide shaft apertures are shaped to closely receive the outside surface of an associated one of said bushings therein.

37 A progressive die as set forth in claim 36, wherein:

• said base plate has a predetermined length, width and thickness;
• and
• said base is cut to length from a bar of steel having a width and thickness substantially commensurate with the predetermined width and thickness of said base plate to minimize machining said base plate.

38 A progressive die as set forth in claim 37, wherein:

• said guide shafts are constructed from a hardened steel, such that said base plate need not be hardened after assembly of said stock lifter.

39 A progressive die as set forth in claim 38, wherein:

• said bar from which said base plate is cut is constructed from 4140 cold drawn steel.

43 A method as set forth in claim 42, wherein:

• said bar selecting step includes selecting the bar from 4140 cold drawn steel, so as to reduce machining operations.

44 A method as set forth in claim 43, wherein:

• said first and second mounting aperture forming step comprises drilling the first and second mounting apertures completely through the bar to avoid grinding.

45 A method as set forth in claim 44, including:

• forming internal threads in the spring unit aperture of the base plate;
• and
• forming external threads in the spring unit base portion which mate with the internal threads of the spring unit aperture, such that rotation of said spring unit base relative to said base plate varies the axial position of said rod portion relative to said lifter bar to permit making stock lifters having different vertical lifts.

46 A method as set forth in claim 45, including:

• mounting a lock fastener in the base plate to engage the base portion of the spring unit to retain the base portion in a selected rotational position in the base plate.

47 A method as set forth in claim 46, including:

• inserting fasteners through the third and fourth mounting apertures in the lifter bar, and connecting second ends of the guide shafts the lifter bar;
• and
• connecting stops to the first ends of the guide shafts, which have radially extending collars that selectively abut the base plate to limit reciprocation of the lifter bar.