U.S. patent number 3,926,083 [Application Number 05/507,637] was granted by the patent office on 1975-12-16 for die set with two-part leader pins.
Invention is credited to Kasimir Janiszewski.
United States Patent |
3,926,083 |
Janiszewski |
December 16, 1975 |
Die set with two-part leader pins
Abstract
Disclosed herein is a die set in which the punch holder is
guided for reciprocating movement towards and away from the die
shoe by two-part leader pins, with the upper leader pin portions
fixed to the punch holder and the lower leader pin portions fixed
to the die shoe. Tapered surfaces on the upper leader pin portions
are received in tapered sleeves on the lower leader pin portions to
guide the movement of the punch holder. The tight fit of the
tapered surfaces minimizes deflection of the punch holder to
provide more accurate punching. Provision is also made for
selecting the depth of stroke of the punch holder, and thus the
punch, by utilizing a boss or stop on the end of the upper leader
pin portion, which stop engages an abutment on the lower leader pin
portion. The boss can be ground to the selected length to provide
the desired travel of the punch holder and punch with respect to
the work material and female die portion.
Inventors: |
Janiszewski; Kasimir (Franklin,
WI) |
Family
ID: |
24019502 |
Appl.
No.: |
05/507,637 |
Filed: |
September 20, 1974 |
Current U.S.
Class: |
83/637 |
Current CPC
Class: |
B21D
28/02 (20130101); B21D 37/10 (20130101); Y10T
83/8855 (20150401) |
Current International
Class: |
B21D
37/00 (20060101); B21D 28/02 (20060101); B21D
37/10 (20060101); B26D 005/20 (); F16C
029/02 () |
Field of
Search: |
;83/637,635,698,638
;308/4C |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Abercrombie; Willie G.
Attorney, Agent or Firm: Fuller; Henry C.
Claims
What is claimed is:
1. In a die set including a punch holder and a die shoe, the
improvement comprising an upper leader pin portion mounted on said
punch holder and having a tapered surface decreasing in diameter
remote from said punch holder, a lower leader pin portion anchored
in said die shoe and having a tapered bore complementary to said
tapered surface of said leader pin and adapted to telescopically
and reciprocally receive said upper leader pin tapered portion and
guide said punch holder during reciprocal movement of said punch
holder and leader pin toward and away from said die shoe.
2. In a die set including a punch holder and a die shoe, the
improvement comprising an upper leader pin portion mounted on said
punch holder and having a tapered surface decreasing in diameter
remote from said punch holder, a lower leader pin portion connected
to said die shoe and having a tapered bore adapted to receive said
upper leader pin tapered portion and guide said punch holder during
reciprocal movement of said punch holder toward and away from said
die shoe and wherein said bore is formed by a sleeve separable from
said lower leader pin portion, and said sleeve has a bore for
receiving said upper pin portion, and means for adjustably
connecting said sleeve on said lower pin portion.
3. In a die set including a punch holder and a die shoe, the
improvement comprising an upper leader pin portion mounted on said
punch holder and having a tapered surface decreasing in diameter
remote from said punch holder, a lower leader pin portion connected
to said die shoe and having a tapered bore adapted to receive said
upper leader pin tapered portion and guide said punch holder during
reciprocal movement of said punch holder toward and away from said
die shoe and wherein said upper leader pin portion has an
adjustable stop and wherein said lower leader pin portion has an
abutment portion engageable with said stop to limit travel of said
punch holder.
4. The improvement of claim 3 wherein said stop comprises a
projecting boss extending axially of said upper leader pin portion,
the boss having a diameter less than said leader pin.
5. The improvement of claim 2 wherein said tapered surfaces of said
upper and lower leader pin portions have a slope such that said
surfaces mate at a pre-selected point in the travel of the punch to
prevent deflection of the punch.
6. The improvement of claim 2 wherein said upper leader pin portion
has intersecting axially and circumferentially extending oil
grooves and including an oil reservoir in said lower leader pin
portion.
7. The improvement of claim 3 wherein said adjustable stop
comprises a threaded bore in said upper leader pin portion and a
screw threadably received in said bore and adapted to engage said
lower leader pin portion.
8. A die set in accordance with claim 2 wherein said punch holder
has a tapered opening for receiving tapered surfaces on said upper
leader pin portions with the tapered openings increasing in
diameter toward the punch holder surface remote from the die
shoe.
9. A die set having a punch holder and die shoe, the improvement
comprising a mounting lug on said punch holder connectable with a
ram, said mounting lug including a tapered shank portion and an
aperture in said punch holder having a tapered surface for
receiving said tapered lug surface, said aperture having its
largest diameter at the punch holder surface adjacent the die shoe.
Description
SUMMARY OF THE INVENTION
The invention provides a die set which employs two-part leader pins
for guiding reciprocal movement of the punch holder with respect to
the die shoe and for controlling the length of travel of the punch
holder towards the die shoe. Tapered male and female surfaces on
adjacent ends of the two-part leader pins provide for a precise
positioning of the male die or punch with respect to the female die
with minimal deflection when the work material is engaged. The
tapered surfaces are adjusted so that they are in shear when the
punch is engaged with the work material so that there is no lateral
deflection or translatory displacement of the punch for more
accurate work than with a conventional die set.
Means are provided for adjusting the fit of the tapered surfaces
and for adjusting the depth of penetration for precise control of
the punch. This is particularly desirable when punching thin stock
such as with a lamination die for transformer plates. With the die
set of the invention the punch can be controlled so that the punch
does not enter the female die, which results in a longer life for
the punch.
Further objects, advantages and features of the invention will
become apparent from the following disclosure.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of a die set embodying the
invention in fragmentary section and showing the punch and punch
holder in retracted and advanced position.
FIG. 2 is a sectional view in reduced scale along line 2--2 of FIG.
1.
FIG. 3 is a fragmentary sectional view of a modified embodiment of
the invention.
FIG. 4 is a fragmentary sectional view of a further modified
embodiment of the invention.
DETAILED DESCRIPTION
Although the disclosure hereof is detailed and exact to enable
those skilled in the art to practice the invention, the physical
embodiments herein disclosed merely exemplify the invention which
may be embodied in other structure. The scope of the invention is
defined in the claims appended hereto.
The die set conventionally includes a punch holder 10 connected to
a mounting lug 12, and a die shoe 14. The punch holder 10 carries a
punch or male die member 16, and a female die 18 is supported on
the die shoe 14. In accordance with the invention there are
provided upper leader pin portions 20 which can have a tapered
shank 22 and be in a press fit in apertures 24 in the punch holder
10. The leader pin portions 20 are also provided with a tapered
surface 26 which can be a continuation of tapered surface 22.
The leader pins 20 can also include an adjustment boss or stop 28
which projects axially form the lower surface 30 of the tapered
portion 26. The purpose of the adjustment boss 28 will be
hereinafter described in detail.
The lower leader pin portions 32 can have tapered surfaces 34
received in tapered apertures 36 in the die shoe. Projecting above
the die shoe is a lower leader pin shank portion 38. Shank portion
38 is connected to a sleeve 40 which is provided with an internal
tapered surface 42 complementary to the tapered surface 26. Means
are provided for adjustably securing the sleeve 40 to the lower
leader pin portion 32. In the construction disclosed in FIG. 1, the
means comprises set screws 44. The set screws 44 enable adjustment
of the position of the sleeve 40 relative to the die 18 or material
to be punched 39 so that the tapered surfaces are in tight
engagment or in shear at a point during penetration of the work
material which enables separation of the punched blank from the
work material 39 with no deflection of the punch.
In use of the die set thus described, the adjustment boss or stop
28 constitutes an adjustable stop which limits downward movement of
the punch as it engages the top 41 of the lower leader pin portion
38. The user of the die set can thus grind the stop 28 to the
desired depth to control travel of the punch and the depth of
penetration of the punch into the female die 18. The adjustment of
sleeve 40 is also taken into consideration when adjusting the stop
28. Although a stop 28 is shown in FIG. 1, if the die set and thus
the leader pins are quite small, the stop 28 can be eliminated and
the surface 30 of the upper leader pin portion can be ground to the
correct length. The surface 30 and surface 41 will limit travel of
the punch holder to the selected distance.
FIG. 3 shows a modified embodiment of the invention in which the
upper leader pin portion 50 is provided with a threaded bore 52
which receives a set screw 54 which is adjusted to set the travel
of the punch holder and punch.
FIG. 4 shows a further embodiment in which the upper leader pin
portion 60 is provided with circumferential oil grooves 62
intersected by axially-extending oil grooves 64. The adjacent ends
66, 68 of the upper and lower leader pins can be provided with
bores 70, 72 to serve as oil reservoirs for lubricating oil 78. The
reciprocating movement of the upper leader pin portion 60 in sleeve
76 provides a pumping action to force oil between the ends 66 and
68 into the grooves 62, 64. The lubricating arrangement as thus
described considerably lengthens the intervals for oil replacement
which minimizes scoring and wearing problems which exist with
conventional die sets.
As shown in FIG. 1, the mounting lug 12 for the punch holder is
desirably provided with a tapered shank portion 80 which fits in a
tapered opening 82 in the punch holder. The lug 12 is thus secured
against withdrawal or severance from the punch holder 10 during
upward movement of the punch holder 10.
The upper and lower leader pin portions are also provided with
tapered surfaces to prevent withdrawal. The tapered surfaces 22 and
36 on the leader pins prevent separation of the leader pins from
the punch holder and die shoe during use. The ram prevents
withdrawal of the pin portions 20 from the punch holder during
downward movement of the punch holder and the bolster plate 84
prevents withdrawal of the lower pin portions 32.
The tapered surfaces 26, 42 of the upper leader pin portion 20 and
the sleeve 40 desirably have a taper of about 0.003 inches per inch
although the taper is more pronounced in the drawings.
The use of two-part leader pins with tapered guiding surfaces and
abutting ends enables control of the punch so that no penetration
of the female die occurs. Thus wear of the male and female die is
reduced to a minimum. In the event wear of the punch does occur and
the punch is ground, the boss 28 or the end of the upper leader pin
portion is also ground to maintain the travel of the punch at the
selected distance.
* * * * *