U.S. patent application number 12/160514 was filed with the patent office on 2008-12-11 for formation tool for a punching machine.
Invention is credited to Albrecht Schneider.
Application Number | 20080302163 12/160514 |
Document ID | / |
Family ID | 38169976 |
Filed Date | 2008-12-11 |
United States Patent
Application |
20080302163 |
Kind Code |
A1 |
Schneider; Albrecht |
December 11, 2008 |
Formation Tool for a Punching Machine
Abstract
A formation tool is used for deforming sheet metal on punching
machines. The formation tool has an upper or top die tool and a
lower or bottom die tool. Toward the top die, there is an upper
mold insert movable relative to a holding-down device, and toward
the bottom die, a lower mold insert movable relative to a stripper
plate. The deformation of the metal sheet is effected upward with
respect to a punching stroke plane. The formation tool has a
lifting device for aiding in lifting the lower mold insert from an
initial position which is at or below the punch stroke plane before
a deforming operation, to a level above the punching stroke
plane.
Inventors: |
Schneider; Albrecht;
(Oberursel, DE) |
Correspondence
Address: |
STITES & HARBISON PLLC
1199 NORTH FAIRFAX STREET, SUITE 900
ALEXANDRIA
VA
22314
US
|
Family ID: |
38169976 |
Appl. No.: |
12/160514 |
Filed: |
January 11, 2007 |
PCT Filed: |
January 11, 2007 |
PCT NO: |
PCT/US07/00657 |
371 Date: |
July 10, 2008 |
Current U.S.
Class: |
72/355.2 ;
72/352; 72/361 |
Current CPC
Class: |
B21D 22/02 20130101 |
Class at
Publication: |
72/355.2 ;
72/352; 72/361 |
International
Class: |
B21D 24/00 20060101
B21D024/00; B21J 13/02 20060101 B21J013/02; B21J 13/08 20060101
B21J013/08; B21D 24/16 20060101 B21D024/16 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 11, 2006 |
DE |
102006001389.1 |
Claims
1. A formation tool for sheet metal deformation on a punching
machine, said die tool comprising: an upper top die tool; a lower
bottom die tool; a holding-down device; a stripper plate; an upper
mold insert being movable relative to the holding-down device, and
cooperating with a lower mold insert, movable toward the bottom die
relative to the stripper plate, to deform a metal sheet upward
relative to a punching stroke plane; and a lifting device for
aiding in lifting the lower mold insert from an initial position
which is at or below the punch stroke plane before a deforming
operation, to a level above the punching stroke plane.
2. The formation tool of claim 1, wherein an upper edge of the
stripper plate, toward the bottom die, is located at the level of
the punching stroke plane.
3. The formation tool of claim 1, wherein the lifting device
comprises a lifting element, disposed in a workbench, and a final
control element disposed on the lower end of the lifting
element.
4. The formation tool of claim 3, wherein the lifting element has a
tubular body.
5. The formation tool of claim 4, wherein the tubular body has at
least one lateral opening in a lower portion of the tubular
body.
6. The formation tool of claim 5, wherein the tubular body has two
diametrically opposed openings in a lower portion of the tubular
body.
7. The formation tool of claim 4, wherein the final control element
has a piston, which engages the lower end of the tubular body.
8. The formation tool of claim 7, wherein the piston has a
cylindrical protrusion, whose outer diameter is essentially equal
to the inside diameter of the tubular body.
9. The formation tool of claim 8, wherein the cylindrical
protrusion is embodied in gable form on its face end, and the lower
sides are located at the level of the lower edges of the two
lateral openings, and the apex of the gable forms a protrusion,
between the two openings, that divides the tubular body.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a formation tool for use in
a punching machine for sheet metal deformation and, in particular,
to a formation tool which has an upper or top die tool and a lower
or bottom die tool for use in a punching machine having a gripper
system which transports the two tool parts for a single machining
operation.
BACKGROUND OF THE INVENTION
[0002] Prior punching machines include revolver punches and
TRUMPF.RTM. system punches. In revolver punches, the top die tools
and bottom die tools are each received in a revolver-like tool
holder. Unlike revolver punches, the TRUMPF.RTM. system has a
gripper system which transports the two tool parts, each for one
machining operation, and inserts them into a processing station.
The TRUMPF.RTM. system can use both punching tools and formation
tools. Formation tools can be used to produce reliefs, folds,
eyelets, or other shapes in sheet metal workpieces.
[0003] The sheet metal workpieces to be processed are moved
horizontally on a workbench in what is referred to as a punching
stroke plane, so that the workpiece can be positioned properly at
the processing station. Deformations are, as a rule, done in an
upward direction to prevent the workpiece, upon a motion for
subsequent processing operations, from sliding onto what then are
downward protrusions instead of sliding onto its flat underside.
However, a prerequisite of the upward deformation of the sheet is
that in a formation tool, the lower mold insert during a deforming
operation remains at a level above the punching stroke plane.
[0004] In prior formation tools, a rigid lower mold insert is
provided which, in accordance with the deformation to be done,
protrudes past the level of the punching stroke plane. In order for
the sheet metal workpiece to be transported properly and without
damage to the processing station, in conventional formation tools,
it is necessary for the stripper plate toward the bottom die, in
its initial position, to rest with its top side at the level of the
upper edge of the lower mold insert. This means that the sheet
metal workpiece, on being transported to the processing position,
must be lifted to the level of the lower mold insert via lateral
stop chamfers on the stripper plate. In the case of vulnerable
surfaces, this can cause processing scratches on the underside of
the sheet metal workpiece. In the ensuing deforming operation, the
holding-down device of the upper tool insert presses the sheet down
laterally of the two aligned mold inserts, so that the desired
formation takes place. When the upper or top die tool is lifted
again, springs then lift the sheet metal workpiece again and it is
moved laterally, whereupon it is again shifted downward onto the
punching stroke plane, so that once again there is a risk of damage
to the underside of the workpiece.
SUMMARY OF THE INVENTION
[0005] An object of the present invention is to create a formation
tool which permits deformation processing of sheet metal workpieces
on punching machines, such as those of the TRUMPF.RTM. system,
without requiring that the workpieces be lifted out of the punching
stroke plane when being transported to the processing position.
[0006] According to the invention, this object is attained by a
formation tool in which the formation tool has a lifting device for
aiding in lifting the lower mold insert from a level at or below
the punching stroke plane before a deforming operation to a level
above the punching stroke plane.
[0007] The formation tool of the present invention offers the
advantage that in an initial position, no part of the lower bottom
die tool protrudes past the level of the punching stroke plane so
that the sheet metal workpiece can be transported to the processing
position without a change in its horizontal position. Next, in the
cooperation of the lifting device with a punching stroke of the
punching machine, a desired deformation is made in the sheet metal
workpiece. It does not matter whether--as is preferred--first the
lower mold insert is lifted by actuation of the lifting device and
then the punching stroke is performed, or vice versa. The
synchronous motion of the lifting device with the punching stroke
is also readily available. Because the initial position of the
sheet metal workpiece is at the lower level of the punching stroke
plane, the formation tool of the present invention now permits a
larger variety of possible shapes, which can be nearly twice as
high as those that can be made with formation tools of the prior
art.
[0008] One advantageous embodiment of the invention comprises an
upper edge of the stripper plate toward the bottom die disposed at
the level of the punching stroke plane. This configuration allows
for an especially favorable contact of the sheet metal workpiece
with the device during the shifting operation, providing for a
maximum capacity for a change in shape.
[0009] In a further preferred embodiment of the invention, the
lifting device substantially comprises a lifting element, disposed
in a workbench, and a final control element disposed on the lower
end of the lifting element. The lifting element has a cross section
appropriately sized for the opening in the processing station. The
disposition of the final control element on the lower end offers
the advantage that the final control element itself need not be
accommodated in the workbench, but instead can be disposed in the
free space existing below the workbench. There is also sufficient
space to accommodate the hydraulic, pneumatic, or electric
connection lines that are required, depending on the type of final
control element.
[0010] In an especially preferred embodiment of the invention, the
lifting element is in the form of a tubular body. The tubular body
first offers the advantage that the lifting device can remain in
the processing station even if the top die tool and bottom die tool
of the formation tool are not used and a punching tool is, for
instance, used instead. In that case, the tubular body offers the
opportunity for punched-out sheet metal parts to drop downward
through its interior to under the workbench and be transported away
from there. Moreover, a tubular body is a relatively lightweight
lifting element, which is nevertheless capable of absorbing the
forces between the final control element and the workpiece that
occur during the forming operation.
[0011] In a further preferred embodiment of the invention, it is
provided that the tubular body, in its lower region, has at least
one lateral opening, preferably two diametrically opposed openings.
The openings serve to allow pressed-out sheet metal parts to fall
laterally out of the tubular body, which makes it possible in a
still further preferred embodiment of the invention to have a
piston of the final control element engage the lower end of the
tubular body. Such an arrangement is more favorable from the
standpoint of stability than to have the final control element
engage the tubular body laterally and for the tubular body to be
open at the bottom, allowing the punched parts could fall directly
downward out of the tubular body. However, in principle, both
embodiments are possible.
[0012] In the case of a piston engaging the lower end of the
tubular body, it is especially preferable to include a cylindrical
protrusion whose outer diameter is equivalent to the inside
diameter of the tubular body. In this configuration, a secure
engagement of the piston inside the tubular body transmits the
forces required during a punching operation.
[0013] Preferably, the cylindrical protrusion has a gable end, and
the sides are located at the level of the lower edges of the two
lateral openings, and the apex of the gable forms a protrusion,
between the two openings, that divides the tubular body. The gable
end of the protrusion of the piston assures that punched-out sheet
metal parts can no longer fall out of one of the two openings,
which prevents punching waste from accumulating in the tubular
body, where after a certain number of punching operations they can
plug it up.
BRIEF DESCRIPTION OF THE FIGURES
[0014] Below, one exemplary embodiment of the invention is
described in conjunction with the accompanying drawings.
[0015] FIG. 1 shows a longitudinal section through a formation tool
of the prior art;
[0016] FIG. 2 shows a longitudinal section through a formation tool
of the present invention;
[0017] FIG. 3 is a comparative longitudinal section of a bottom die
tool of the prior art and a bottom die tool of the present
invention with an associated lifting element and a sheet metal
workpiece located in the punching plane;
[0018] FIG. 4 shows the bottom die tool of FIG. 3 with the lifting
element raised;
[0019] FIG. 5 is a section through a lower machining station of a
punching machine of the TRUMPF.RTM. system, with the bottom die
tool of the invention inserted and with an associated lifting
device;
[0020] FIG. 6 is a fragmentary sectional view of the lifting device
of FIG. 5; and
[0021] FIG. 7 is a fragmentary sectional view, rotated 90.degree.,
of the lifting device of FIG. 6.
DETAILED DESCRIPTION
[0022] In FIG. 1, a prior art formation tool 100 is used in
punching machines of the TRUMPF.RTM. system for forming sheet metal
workpieces 102. The formation tool comprises an upper or top die
tool 104 and a lower or bottom die tool 106, which can each be
inserted into respective mounts in a processing station. To that
end, the top die tool 104 has a suitably shaped shaft 108, while
the bottom die tool 106 has a contact face 110 and, with a
cylindrical protrusion 112, engages a corresponding recess in the
processing station.
[0023] The top die tool 104 has an upper mold insert 114, which is
braced via a helical spring 116 on a top die body 118. A
holding-down device 120 is also solidly joined to the top die body
118 and presses the sheet during a punching stroke against a
stripper plate 122 of the bottom die tool. The stripper plate 122
is braced resiliently on a bottom die body 126 via helical springs
124, with which body a lower mold insert 128 is rigidly connected
and cooperates with the upper mold insert 114, in order for a
punching stroke to form a relief 130 in the sheet metal workpiece
102. Such deformations are, as a rule, molded upward, so that the
workpiece can be moved sliding on its underside, whereas downward
formed deformations would interfere.
[0024] The location of the bottom die tool 106 in the processing
station can be seen on the left-hand side in FIG. 3. A punching
stroke plane 132 is defined by the location of the workpiece 102,
shown here slightly elevated, on the workbench. The workpiece 102
is braced by holders 134 with brushlike protrusions 136. It can be
seen clearly from FIG. 3 that the lower mold insert 128 protrudes
markedly past the punching stroke plane 132, and the stripper plate
122, in the initial position shown, is in alignment with the upper
edge of the mold insert 128. If the workpiece 102 is to be movable
at all into the processing station when the formation tool 100 is
located there, the edges of the stripper plate 122 have stop
chamfers 138, so that on being transported to the processing
station the workpiece 102 is raised above the level of the mold
insert 128. If there are vulnerable surfaces on the underside of
the workpieces 102, damage that is at least problematic visually
can occur, so that this surface can no longer be used as a visible
surface if, for instance, only a coating with clear lacquer is to
be applied or if no further treatment whatsoever is
contemplated.
[0025] In FIG. 2, a formation tool 10 according to the present
invention is shown, which avoids raising the workpiece 102 in the
processing station. The formation tool 10 comprises a top die
insert 14 and a bottom die insert 16, whose connection dimensions
are such that they fit into the corresponding tool holders of a
punching machine of the TRUMPF.RTM. system. Accordingly, the top
die insert 14 has a shaft 18, which corresponds to the shaft 108 of
the top die insert 100, shown in FIG. 1. The bottom die insert 16
has a contact face 20, with which it rests in a contact region of
the processing station (FIG. 5).
[0026] The top die insert 14 also has an upper mold insert 24,
which is braced via a helical spring 26 on a top die body 28. A
holding-down device 30 guides the upper mold insert 24, and the
most essential difference on the part of the top die insert 14
shown in FIG. 2, compared to the top die insert 114 shown in FIG.
1, is that the possible stroke length of the upper mold insert 114
is increased by the widened recess 31 in the top die body. This is
illustrated by the two reference symbols x.sub.1 in FIG. 1 and
x.sub.2 in FIG. 2.
[0027] A bottom die body 36 forms the stripper plate, while a lower
mold insert 38 is braced on the bottom die body 36 via helical
springs 34 for bottom die tool 16. The lower mold insert 38 is
formed integrally with an insert plate 32, but alternatively can be
designed separately from it as a separate or discrete part. The
insert plate 32 has a cylindrical outer circumference 22 which fits
into a recess of the processing station (FIG. 5).
[0028] As can be seen from FIG. 3, in the relaxed or initial
position, all parts of the bottom die tool 16 are located below the
punching stroke plane 132, so that when there is a formation tool
10 in the processing station, the workpiece 102 can be transported
to the processing position without a change in the level or
horizontal height of the workpiece. To enable performing a
deformation process that is oriented upward, it is then necessary,
however, either before or during the performance of the punching
stroke, to raise the lower mold insert 38, with the insert plate
32, to the processing position shown in FIG. 4 with the aid of a
lifting element 42 formed as a tubular element. With the lower mold
insert 38 in its raised position, the punching stroke is then
performed, so that the relief 140 can be made in the workpiece 102.
Because of the lower level of the stripper plate 36, a greater
deformation distance is now possible relative to that of a
conventional tool, as indicated by the relief 140 and the reference
symbols x.sub.3 in FIG. 1 and x.sub.4 in FIG. 2. The greater
relative stroke necessary for this, between the upper mold insert
24 and the top die body 28, is realized by means of the larger
recess 31, previously mentioned, and the longer stroke length of
the mold insert 24 that this makes possible.
[0029] As noted, in comparison to the prior art formation tools,
such as formation tool 100, the present formation tool 10 has a
movable lifting element, such as piston 46, which is a component of
a lifting device 44 (FIG. 5). The lifting piston 46 is connected to
a hydraulic, pneumatic, or electric final control element. In FIG.
5, the lower tool receptacle 48 of a processing station of a
punching machine of the TRUMPF.RTM. system is shown. This kind of
tool receptacle 48 is well known in the art and therefore there is
no need to describe it in further detail.
[0030] The tool receptacle 48 has a contact face 50 on which a
spacer ring 52 is disposed. The inside diameter of the spacer ring
52 essentially corresponds to a recess 54 in the workbench, into
which recess the insert plate 32 protrudes, and in which recess the
tubular lifting element 42 is disposed. The tubular body 42, in
contrast to the top die tool 14 and the bottom die tool 16, is not
removed from the processing station when a punching operation, for
instance, is to be performed in it with a correspondingly provided
punching tool. This kind of removal would not be readily possible
because of the great length of the tubular body 42, even if the
tubular body 42 were detachably disposed on the piston 46. However,
because the lifting element 42 is a tubular body, its removal is
not even necessary, since the inside cross section of the tubular
body 42 offers enough free space for punched-out sheet metal parts
to drop downward. To keep the punching waste from accumulating in
the tubular body 42, two diametrically opposed openings 56 are
provided in its lower region, through which the punching waste can
fall laterally out of the tubular body 42.
[0031] Openings 56 and piston 46 can be seen in greater detail in
FIGS. 6 and 7. The two openings 56 are shaped in such a way that
between them, relatively wide wall portions 58 remain, which can
absorb the forces that occur in operation. The central engagement
of the piston 46 with the lower end of the tube has proved
advantageous because the forces can be transmitted especially well,
and without further securing flanges, between the final control
element and the tubular body 42. To enable the punching waste to
fall securely out of the lateral openings 56, the piston 46 has a
cylindrical protrusion 60 at its top, and the top of the protrusion
has a gabled end. The lower edges 62 of the gabled end are
approximately flush, in the middle region, with lower edges 64 of
the openings 56, while the apex 66 of the gable forms a protrusion
between the two openings 56 that divide the hollow body. In
conjunction with the slopes of the gable, this protrusion 66
assures that the punching waste will be securely carried to the
outside through the lateral openings.
[0032] As a rule, the course of the deforming operation will be
such that before the punching stroke of the punching machine is
performed, the piston 46, with the aid of the final control
element, will first lift the tubular body 42 and, thus, also the
insert plate 32 and the lower mold insert 38. In this way, work can
be done with very slight adjusting forces. A self-locking drive,
for instance, can then absorb the much stronger forces that occur
during the deforming operation. In principle, however, it is also
possible to perform the punching stroke and the lifting motion of
the lifting device synchronously, or even, given a suitable
embodiment of the final control element, to provide a course in
which first the top die tool is lowered onto the surface of the
workpiece, and then the shaping operation is performed with the aid
of the lifting device 44.
[0033] Depending on the form of the formation tools, reliefs,
louvers, beads, reliefs, folds, and other shaping machining
operations can be performed.
[0034] It will now be clear to one of ordinary skill in the art
that formation tool 10 provides advantages over prior devices,
especially wherever workpieces have a surface that is especially
vulnerable to scratching, or where major changes in shape are
important, which are made possible by the relatively lower disposed
stripper plate 36.
[0035] Although the invention has been described in considerable
detail with respect to preferred embodiments, it will be apparent
that the invention is capable of numerous modifications and
variations, apparent to those skilled in the art, without departing
from the spirit and scope of the claims.
* * * * *