Note: Descriptions are shown in the official language in which they were submitted.
1061706
The present invention relates generally to a cutting
press, employing a novel cutting edge configuration.
Several unsolved problems have existed in the art of
cutting devices prior to the present invention. For example, many
cutting devices have somewhat elaborate cutting configurations
which are costly to form on the cutting blade. Many other cutting
blade arran~ements simply do not give a clean cut on the stock
material as desired.
Still other problems arise in connection with a cutting
die press. For example, many of the prior art cutting blades
require a relatively high tonnage or force to press the cutting
blade entirely through the stock material. In die presses where
a resilient die pad is used, inordinate wear of the die pad has
been experienced with various types of notched blades because of
the cutting blade cutting away the die pad after it has sliced
through the stock material. If a hard metallic back up die pad
is used, the cutting blade is dulled by metal-to-metal contact
after the cutting operation.
Specific examples of prior art cutting blade configura-
tions are disclosed in United States Patents Nos. 3,277,764 to
Henc, 3,422,712 to Lovas, and 201,104 to Frary. Each of these
~ prior art devices likewise include inherent disadvantages not
`~ experienced by the present invention.
In short, the prior art does not provide the overall
`~ range of advantages or the structural arrangement or method of
cutting edge disclosed herein.
According to the present invention, there is provided a
-~ cutting press including a resilient die pad aligned with an axial-ly reciprocal die rule, the improvement of the die rule having a
cutting surface defined by (a) a plurality of generally equally
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spaced piercing points and (b) a plurality of cutting edge
between the piercing points, each of the cutting edges extending
from a piercing point toward a next adjacent piercing point for
substantially the entire distance between the two piercing points,
the cutting edges extending in a direction away from the die pad
at an angle in side elevation of the die rule with a line through
the tips of the piercing points of between about one and fifteen
degrees, thereby forming a generally check-marked shaped cutting
surface valley between adjacent piercing points, the valley having
1~ a depth of not more than three sixteenths of an inch, and the die
rule piercing points thereby having to penetrate into the resi-
lient die pad for a distance equal only to the depth of the cutting
surface valley for the die rule to completely cut through the
thickness of the material being cut.
This invention will more fully appear from the following
description of an embodinlent with reference to the accompanying
drawings, in which:
Figure 1 is a schematic, cross-sectional view of a die
press which includes a cutting tool having the cutting edge confi-
guration of the present invention;
Figure 2 is a perspective view of the cutting tool ofFigure l;
Figure 3 is a schematic, partially cross-sectional view
o~ another die press and cutting tool in combination with a punch
~ tool;
"~ Figure 4 is a perspective view of the cutting tool of
Figure 3; :
, Figures 5-10 are perspective views of various cutting
` tools which may include the cutting configuration of the present
; 30 invention; ~ .
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Figure 11 is an enlarged, fragmented plan view of one
embodiment of the cutting edge configuration;
Figure 12 is an enlarged, fragmented side elevational
view of the cutting edge configuration of Figure 11;
Figure 13 is a cross-sectional view taken along plane
13-13 of Figure 12.
Referring to the drawings, Figure 1 illustrates a cutting
pre~s 10 which is primarily suited for use in cutting thick or
tou~h materials, such as soft metallic materials. The die press
10 includes a fixed die base 12 surmounted by and connected to
mounting plate 14 in a conventional manner. A male punch 16 and
a resilient stripper pad 18 are suitably mounted on top of
mounting plate 14 for receiving stock material 20. The stock
material is cut with a flat die rule 22 which is shown in per-
; spective in Figure 2. The cutting edge of die rule 22 includes a
plurality of side-by-side notched configurations 23 which form a
novel cutting edge that will be more fully explained below.
Die rule 22 is mounted in a die rule mounting block 24,
which is illustrated as being a wood block. Mounting block 24
is suitably mounted to a back up plate 26 which i9 connected to a
punch holder 28. A compressible stripper pad 30 is also attached
to mounting block 24 in conventional manner and comprises, for
example, hard rubber as is somewhat conventional in the art. The
die rule 22, stripper pad 30, mounting block 24, back up plate 26, ~-
and punch holder 28 comprise a vertically reciprocal cutting die. ~ ~
Operation of the embodiment of Figure 1 includes -
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raising the cutting die so that a piece of stock material 20
may be properly positioned on male punch 16 and stripper pad 18.
The cutter die is then driven under pressure downwardly so that
the die blade 22 severs the stock material to form a blank of
predesired configuration, thereby leaving scrap material 33.
As illustrated, die rule blade 22 cuts through the stock
material and barely extends into a slot 32 defined between punch
16 and stripper pad 18. Downward movement of the die press i~
limited substantially to the position shown in Figure 1, so
that the cutting edge on rule 23 does not strike mounting plate
14. As the die rule blade 22 projects into slot 32, the
stripper pad 30 is compressed. Then as the die press is raised,
stripper pad 30 expands and leaves the cut stock material on
punch 16.
Figure 3 illustrates a die press primarily suited for
cutting soft stock material. This embodiment includes a fixed
base 42 and a vertically reciprocable punch holder 44 to which
back up plate 46, mounting block 48, and die rule blade 50 are
mounted. In this particular embodiment, the die rule blade is
cylindrical as shown in Figure 4 and includes a plurality of
side-by-side notches 52 in accordance with the present inven-
`~ tion~ Also in this embodiment, a punch 54 is suitably mounted
in mounting block 48, and may include the cutting edge config-
uration of this invention.
In operation of the embodiment in Figure 3, the punch -
; holder 44 is raised from the position illustrated and a piece
of stock material 56 is properly positioned on a resilient die
; pad 58. Die pad 58 is suitably mounted on the fixed base 42 and
.
is comprised of a rubber or polyurethane material. Scrap
- 30 material is formed during the cutting operation by punch 54,
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the scrap being removed through a knock-out hole 60 in punch
54, as is conventional.
After the stock material is properly positioned on the
die pad, punch 54 is moved under pressure by suitable power
means, such as a hydraulic cylinder and pi~ton, to drive the
die rule cutting blade through the stock material 56. At about
the same time, punch 54 forms a scrap slug.
As shown in Figure 3, the die rule cutting edge barely
cuts into the die pad. This is necessary so that the notched
configuration of the cutting edge in the present invention will
completely cut through the stock material. However, in later
; portions of this disclosure, it will be explained that the
present invention limits the extent to which the die rule cuts
into the die pad, thereby yielding one of the advantages of the
present invention; i.e., greater die pad longevity, with very
little resurfacing required.
From the embodiments shown in Figures 1 and 3, it
can be readily seen that the cutting edge configuration of this
invention can be used in a variety of ways. Figures 5-10
further illustrate that the cutting edge configuration is not
limited to a die rule, per se, but is virtually unlimited in
its application. For example, Figure 5 illustrates a circular
hole saw 7~ having a shaft 71 and being conventional in every
aspect except the novel cutting edge configuration 72 of the
present invention.
Figure 6 illustrates a flat die rule blade similar
to that of Figure 2 and including a shank 74. A chamfer 75
at the cutting edge of the die rule is formed by two conver-
` ging, generally V-shaped surfaces. The novel cutting edge con-
figuration of this invention is formed on the chamfer 75 and
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includes the plurality of notches and side-by-side peaks 76.
Figures 7 and 8 illustrate cylindrical die rules, or
punches, 78 and 82 having respective chamfer regions 79 and 83. -
In these embodiments, the internal bore of the die rule is
generally cylindrical, but there still exists two converging
surfaces to define the cutting edge. Notches 80 and 84 are
formed on the terminus of the cylindrical die rules to define
the cutting edge configuration of this invention. Each punch
includes a knockout hole 77 and 85, respectively, for scrap
material ejection.
Figure 9 illustrates a slitter wheel 86 including a
circular hole 87 and being conventional in every respect except
for the cutting edge configuration 88 of the present invention.
As is known to those who are skilled in the cutting art, a
. slitter wheel traverses stock material under pressure to effect
the cutting operation.
Figure 10 illustrates another version of a cylindrical
die rule 90 which is substantially similar to die rule 50 illus-
trated in Figure 4. Of course, the cutting edge configuration
92 is that of the present invention.
Figures 11-13 show in enlarged fashion a cutting
edge configuration according to a preferred embodiment of the ~;
the present invention. From Figure 11, it
can be seen that the illustrated tool is a cylindrical die rule
100, similar to that in Figure 10. The die rule 100 includes
a shank 102 and a chamfer formed by converging surfaces 104 and
106. Figure 13 shows the converging sides forming an angle ~
- which in preferred embodiment, should be chosen to fall in the
range of between one and thirty degrees. As discussed pre-
viously in regard to Figures7 and 8, surface 104 could be cylin-
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1061~06
drical, but there would still exist two converging surfaces to
define the die rule cutting region.
The cutting e*ge configuration includes side-by-side
notches or indentations which are formed on only one of the
chamfer converging surfaces, for example, by grinding.
These notches define a plurality of teeth having
generally e~ually spaced peaks 108 which serve to pierce the
stock material to initiate the cutting action. The notches are
also configured to form a plurality of primary cutting or
slicing edges 110, each extending away from one peak into an
associated`notch and toward a next adjacent peak. It can be
seen from Figure 12, that cutting blade edge 110 extends approx-
imately 75 to 80 percent or more of the distance between two
adjacent peaks. For purposes of defining the present invention,
it is considered that this constitutes the primary cutting edge
extending substantially across the entire distance between two
adjacent peaks.
Further, it can be seen from Figure 12 that the
primary cutting edge 110 forms an angle "b" with a line through
20 piercing points 108. According to the invention, this angle
should be no more than about fifteen degrees. More preferably,
the angle should be within the range of between about one and
ive degrees.
Figure 11 also shows that cutting edge 110 forms an
angle `'a" in plan view with a line through peaks 108. This
angle is directly related, in general, to the slope angle of
surface 104 relative to the vertical. This relationship can
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be seen in Figure 13, wherein the notch is illustrated in
phantom. In most instances, this angle "a" will be between
; 30 about one and fifteen degrees, but this is not critical. In
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die rule embodiments having a cylindrical inner bore, such as
in Figures 7 and 8, angle "a" would appear to approach zero for
strict geometrical reasons.
The notched configuration of the present invention
also defines a pair of pyramidal notch surfaces 112 and 114
and an incidentally-occurring secondary cutting edge 116. The
secondary cutting edge, of course, cuts only small portions of
the stock material so that the cutting action is substantially
unidirectionally along primary cutting edge 110 from one
- 10 piercing point to the next. In some embodiments, edge 116 may
even become purely vertical so that the entire cutting action
is along a primary cutting edge 110. For definitional purposes,
surfaces 110 and 116 are considered to constitute a check-marked
shaped edge interconnecting adjacent piercing points.
Pyramidal-shaped surface 112, the major pyramidal
surface, is bounded on one side by primary cutting edge 110 and
- has a common side with secondary pyramidal surface 114. For
definitional purposes, these surfaces are considered to define
a generally boomerang-shaped notch configuration. However, it
is not necessary that the notches be defined by these pyramidal
surfaces. The important consideration would appear to be the
combination of the piercing points, the major cutting edges
establishing progressive angular cutting from one piercing point
to the next, and the notches being formed on only one side of
the chamfer.
`~ Figure 12 also illustrates that the small angle "b"
defines a relatively sha~low valley depth "d". This depth will,
of course, be a direct result of the angle "b" and the distance
between adjacent piercing points. For most applications of the
~0 present invention, this depth will not be more than about three
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sixteenths (3/16) of an inch. In the more preferred embodiments,
the depth of the valley will be no more than about 3/32, and
may even be as shallow as 1/32 and 1/64 of an inch, depending
upon the material to be cut. In the most preferred embodiment,
the valley depth will result from angle "b" being from about 1 to
5. It will be recalled from the discussion relating to the
embodiment of Figure 3 that this shallow valley depth has great
significance when a resilient back up die pad supports the stock
material. Specifically, for a notched die rule blade to com-
pletely cut through stock material the cutting edge portion mustproject completely through the stock material and therefore into
the resilient die pad material. This penetration depth is mini-
mized in the present invention because of the shallow notch
valley depth. Accordingly, the resilient die pad does not ex-
perience the wear associated with prior art notched cutting
edges.
The manner of using a cutting tool having the present
cutting edge configuration is substantially identical to that
` of prior cutting tools. However, the cutting action created by
the present invention is not the same as in the prior art.
Specifically, when tha cutting tool is pressed into the stock
material peaks 108 pierce the material to initiate the cutting
action~ Continued movement of the cutting tool through the
stoc~ material results in a progressive cutting or slicing by
the primary cutting edge substantially unidirectionally from
" one piercing point to the next. Further, the piercing points
and primary cutting edges are formed by a notch which is only
on one side of the cutting tool so that stock material exerts a
resistive pressure substantially on only one side of the cutting
tool which creates a unidirectional cutting pressure on the
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material being cut. These overall structural limitations and
cutting method steps result in the reduced tonnage requirements
previously explained.
It will be understood from the foregoing description
that the rate of cutting action in the direction between the
pierced points on the stock material will be dependent upon the
angle of the cutting edges. Specifically, the cotangent for a
one degree cutting edge is 57.29, the cotangent for a five degree
cutting edge is 11.43 and the cotangent for a fifteen degree
cutting edge is 3.73. Therefore, with a one degree cutting edge,
the stock material will be cut at a rate of about 57.29 times
the rate of relative movement between the cutting tool and stock
material; with a five degree cutting edge, the stock material
between the pierced positions will be cut at a rate of about
11.43 times the rate of relative movement between the cutting
tool and stock material; and with a fifteen degree cutting edge, `
the stock material between the pierced positions will be cut by a
rate in comparison with the rate of relative movement between the
cutting tool and stock material of about 3.73:1.
It is to be understood that the description and explana-
tion herein is merely exemplary of the overall invention and is
not intended to be limiting in any respect. For example, the
cutting edge con~iguration may be formed by other methods than
grindlng and may be used in all equivalent cutting tools.
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