U.S. patent application number 09/731123 was filed with the patent office on 2001-10-18 for bending and hemming method and apparatus.
Invention is credited to Schlafhauser, Joseph K., Wiens, Philip V..
Application Number | 20010029765 09/731123 |
Document ID | / |
Family ID | 26884075 |
Filed Date | 2001-10-18 |
United States Patent
Application |
20010029765 |
Kind Code |
A1 |
Schlafhauser, Joseph K. ; et
al. |
October 18, 2001 |
Bending and hemming method and apparatus
Abstract
A bending and hemming apparatus configured to both bend and hem
a sheet metal panel to form a body closure member at a single
station. The apparatus includes a hemming machine movable between a
retracted position spaced from a bending machine and advanced
positions adjacent the bending machine to assist in the bending
operation and to hem the body panel into a finished product. The
apparatus also includes an anvil assembly pivotably supported on
the hemming machine. The anvil assembly is movable between a
lowered position where it engages the workpiece when the hemming
machine is advanced to a bending position adjacent the bending
machine. In the lowered position, the anvil assembly provides a
fulcrum around which the workpiece is bent. The anvil assembly is
pivotable to a raised position to allow the hemming machine to be
advanced to a hemming position adjacent the bending machine from
which the hemming machine can engage the bent workpiece to hem the
workpiece.
Inventors: |
Schlafhauser, Joseph K.;
(Troy, MI) ; Wiens, Philip V.; (LaSalle,
CA) |
Correspondence
Address: |
REISING, ETHINGTON, BARNES, KISSELLE,
LEARMAN & McCULLOCH, P.C.
P.O. Box 4390
Troy
MI
48099-4390
US
|
Family ID: |
26884075 |
Appl. No.: |
09/731123 |
Filed: |
December 6, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60188438 |
Mar 10, 2000 |
|
|
|
Current U.S.
Class: |
72/312 |
Current CPC
Class: |
B21D 39/021 20130101;
Y10T 29/53791 20150115 |
Class at
Publication: |
72/312 |
International
Class: |
B21D 011/00 |
Claims
What is claimed is:
1. A bending and hemming apparatus comprising: a bending machine
configured to support a metal panel workpiece at a bending station
and to bend the edge of the metal panel workpiece in preparation
for hemming; a hemming machine configured to hem the bent edge of
the metal panel workpiece; the hemming machine being configured to
hem metal panel workpieces while the workpieces are still supported
on the bending machine at the bending station to obviate the need
to transport the workpiece from the bending station to a separate
hemming station following bending.
2. The bending and hemming apparatus of claim 1 in which: the
hemming machine is movable between a retracted position spaced from
the bending machine and advanced bending and hemming positions
adjacent the bending machine; and the apparatus includes an anvil
assembly pivotally supported on the hemming machine for motion
between a lowered position and a raised position, the anvil
assembly engaging and providing a fulcrum for bending the workpiece
when the hemming machine is in the bending position and the anvil
assembly is in the lowered position, the anvil assembly being
movable to the raised position to prevent the anvil assembly from
interfering with the hemming of the bent workpiece when the hemming
machine is advanced to the hemming position.
3. The bending and hemming apparatus of claim 2 in which the
bending machine includes: a fixed lower die part; an upper die part
mounted for pivotal motion relative to the upper die part; a
workpiece retainer mechanism that secures a metal panel workpiece
on the upper and lower die parts; and a bender drive mechanism
operatively connected to the upper die part to rotate the upper die
part relative to fixed lower die part to bend a workpiece secured
on the die parts.
4. A method of both bending and hemming a metal panel workpiece;
the method including the steps of: loading a metal panel workpiece
onto a bending machine; moving an anvil assembly into a position to
act as a fulcrum for subsequent bending of the workpiece; bending
the workpiece a predetermined number of degrees around an anvil
tool portion of the anvil assembly by rotating a movable die
element of the bending machine a predetermined number of degrees;
forming a finished part from the workpiece by actuating the hemming
machine to hem at least a portion of a bent edge of the workpiece;
and actuating the bending machine and hemming machine to release
the finished part.
5. The method of claim 4 in which the step of loading a metal panel
workpiece onto a bending machine includes actuating a workpiece
retainer mechanism of the bending machine to hold the metal panel
in position on the bending machine.
6. The method of claim 4 in which the step of moving an anvil
assembly into a position to act as a fulcrum includes: pivoting an
anvil assembly to a lowered position approximately level with a
portion of the workpiece to be bent; and moving a hemming machine
that pivotably sup ports the anvil assembly to a bending position
adjacent the bending machine.
7. The method of claim 6 in which the step of forming a hemmed part
includes: retracting the hemming machine and anvil assembly from
engagement with the panel; pivoting the anvil assembly to a raised
position; and advancing the hemming machine into a hemming position
adjacent the panel.
8. The method of claim 7 including the additional step of further
bending the workpiece by actuating the bending machine to rotate
the movable die portion of the bending machine to a closed position
after the step of pivoting the anvil assembly to a raised position
and before the step of actuating the hemming machine to hem the
workpiece.
Description
REFERENCE TO PROVISIONAL PATENT APPLICATION
[0001] This application claims the benefit of provisional patent
application Ser. No. 60/188,438 filed Mar. 10, 2000.
FIELD OF THE INVENTION
[0002] This invention relates to an apparatus for bending and
hemming a metal panel into an automotive body closure member such
as a tailgate.
BACKGROUND OF THE INVENTION
[0003] An automotive body panel closure member such as a tailgate
generally comprises both an inner panel and an outer panel that may
be formed from a single sheet of material such as sheet metal. To
form such a body panel, the sheet must be folded upon itself, i.e.,
"doubled-over" and the mating edges joined to provide a finished
and structurally sound component for use on a vehicle. One
well-known process for joining the edges of such a panel is known
in the art as hemming and is accomplished using a hemming machine
that folds the edge of one panel over the edge of the other panel
to mechanically lock the panel edges together.
SUMMARY OF THE INVENTION
[0004] The invention is a bending and hemming apparatus comprising
a bending machine configured to support a metal panel workpiece at
a bending station and to bend the edge of the metal panel workpiece
in preparation for hemming. The apparatus includes a hemming
machine configured to hem the bent edge of the metal panel
workpiece. The hemming machine is configured to hem metal panel
workpieces while the workpieces are still supported on the bending
machine at the bending station to obviate the need to transport the
workpiece from the bending station to a separate hemming station
following bending.
[0005] According to another aspect of the invention, a method is
provided for both bending and hemming a metal panel workpiece. The
method includes loading a metal panel workpiece onto a bending
machine and moving an anvil assembly into a position to act as a
fulcrum for subsequent bending of the workpiece. The workpiece is
then bent a predetermined number of degrees around an anvil tool
portion of the anvil assembly by rotating a movable die element of
the bending machine the predetermined number of degrees. A finally
hemmed part is then formed from the workpiece by actuating the
hemming machine to hem at least a portion of a bent edge of the
workpiece. The bending machine and hemming machine are then
actuated to release the finally hemmed part.
[0006] Objects, features and advantages of this invention include
the ability to bend and hem the edge of a sheet metal workpiece at
a single work station, and to pre-hem the edge of a sheet metal
workpiece at the same work station where initial bending and
hemming occur.
DESCRIPTION OF THE DRAWINGS
[0007] These and other objects, features and advantages of this
invention will be apparent from the following detailed description
of the preferred embodiment and best mode, appended claims, and
accompanying drawings in which:
[0008] FIG. 1 is a diagrammatic front view of a bending and hemming
apparatus constructed according to the invention showing a bottom
end hemming machine of the apparatus in a retracted position, an
anvil assembly of the apparatus in a lowered position, the anvil
assembly shown in a raised position in phantom, and with two side
edge hemming machines and corner units of the apparatus omitted for
clarity;
[0009] FIG. 2 is a diagrammatic front view of the apparatus of FIG.
1 showing the anvil assembly in a lowered position, the hemming
machine advanced to a bending position, a movable die portion of
the bending machine in an open position and with the side edge
hemming machines and corner units omitted for clarity;
[0010] FIG. 3 is a diagrammatic top view of the apparatus of FIG. 2
and also showing the side and corner hemming units omitted from
FIGS. 1 and 2;
[0011] FIG. 4 is a diagrammatic front view of the apparatus of FIG.
1 with the movable die portion of the bending machine in a
partially closed position, the anvil assembly in the lowered
position, the bottom end hemming machine advanced to a hemming
position and with the side edge hemming machines and corner units
omitted for clarity;
[0012] FIG. 5 is a diagrammatic front view of the apparatus of FIG.
1 showing the bottom end hemming machine and anvil assembly in the
retracted position and with the side edge hemming machines and
corner units omitted for clarity;
[0013] FIG. 6 is a diagrammatic front view of the apparatus of FIG.
1 showing the anvil assembly in the raised position, the movable
die post portion of the bending machine in a fully closed position,
and with the side edge hemming machines and corner units omitted
for clarity;
[0014] FIG. 7 is a diagrammatic front view of the apparatus of FIG.
1 showing the position of one of the side hemming machines relative
to the bending machine, showing the bottom end hemming machine
being advanced from the retracted position by a harmonic drive, and
with the corner units omitted for clarity;
[0015] FIG. 8 is a diagrammatic top view of the apparatus of FIG. 1
showing the bottom end hemming machine advanced to the bending
position, showing the relative position of the bending machine and
the side hemming machines, and with the corner units removed for
clarity;
[0016] FIG. 9 is a diagrammatic front view of the apparatus of FIG.
8 with one of the side edge hemming machines and the corner units
removed for clarity;
[0017] FIG. 10 is a diagrammatic top view of the apparatus as shown
in FIG. 6 with the anvil assembly in the lowered position and
corner units removed for clarity;
[0018] FIG. 11 is a diagrammatic front view of apparatus of FIG. 1
showing movable die portion of the bending machine in the opened
position for removal of the part, and with the side edge hemming
machines and corner units omitted for clarity;
[0019] FIG. 12 is a diagrammatic front view of the apparatus of
FIG. 1 with the workpiece, side edge hemming machines and corner
units omitted for clarity;
[0020] FIG. 13 is a diagrammatic top view of the apparatus of FIG.
12 as also shown in FIG. 10 with the corner units omitted for
clarity;
[0021] FIG. 14 is a diagrammatic front view of the apparatus as
also shown in FIG. 2 with the side edge hemming machines and corner
units omitted for clarity;
[0022] FIG. 15 is a diagrammatic top view of the apparatus of FIG.
14 as also shown in FIG. 3;
[0023] FIG. 16 is a diagrammatic front view of the apparatus of
FIG. 1 as also shown in FIG. 7 but including the ball screw drive
rather than a harmonic drive operatively connected to the bottom
end hemming machine;
[0024] FIG. 17 is a diagrammatic top view of the apparatus of FIG.
1 as also shown in FIG. 8 with the corner units removed for
clarity;
[0025] FIG. 18 is a flow chart depicting the sequence of bending
and hemming operations for the apparatus of FIG. 1; and
[0026] FIG. 19 is a diagrammatic front view of an alternative
bending and hemming apparatus constructed according to the
invention.
DETAILED DESCRIPTION
[0027] FIGS. 1-17 illustrate a combination body panel bender and
hemmer apparatus 20 constructed according to the invention. The
apparatus 20 has a turnover station or bending machine 22 with a
fixed lower die 24 supported on a bending machine frame 26 and an
upper die 28 pivotably mounted adjacent the fixed lower die 24 on
the bending machine frame 26. The bending machine 22 also includes
a bender drive mechanism 30 operatively connected to the upper die
28 and configured to rotate the upper die 28 between an open
position, a partially closed position and a fully closed position.
The bending machine 22 also includes a plurality of suction cups 32
or outlets disposed in the upper and lower die portions 28, 24 and
configured to secure a metal panel workpiece 34 in position for
bending on the die portions 24, 28. The bending machine 22 also
includes a vacuum source (not shown) which may be of known
construction in fluid communication with each suction cup of the
plurality of suction cups 32.
[0028] The apparatus 20 also has a lower end hemming machine 38
configured to hem an edge of the workpiece 34 that will become a
lower end of a finished body panel following the bending and
hemming operations. As shown in FIGS. 7, 9 and 16 the lower end
hemming machine 38 includes a pre-hem steel 40 and a final hem
steel 42 that are individually extendable and retractable by a hem
steel drive mechanism 44 as is well known in the art. The lower end
hemming machine 38 is supported on a linear slide 46 for reciprocal
movement between a retracted position remote from the bending
machine 22 and advanced bending and hemming positions adjacent the
bending machine 22. The apparatus 20 also includes a hemming
machine drive 48 operatively connected to the lower end hemming
machine 38 and configured to move the lower end hemming machine 38
translationally on the linear slide 46 between the advanced and
retracted positions. The hemming machine drive 48 may be a harmonic
drive as shown in FIG. 7, a ball screw drive as shown in FIG. 16,
or an air cylinder drive as shown in FIG. 19.
[0029] The apparatus 20 also has a hold-down anvil assembly 50 that
is pivotably supported on the lower end hemming machine 38 for
pivotal movement between a raised position best shown in FIG. 11
and a lowered position best shown in FIGS. 2, 4, 5 and 14. An anvil
assembly drive 52 is operatively connected to the anvil assembly 50
to move the anvil assembly 50 between the raised and lowered
positions. The anvil assembly drive 52 may be either an air
cylinder, an electric motor or any other suitable drive mechanism
known in the art. An anvil tool 54 of the anvil assembly 50 is
removably attached to an arm portion 51 of the anvil assembly 50
that is pivotally supported on the lower end hemming machine 38.
The anvil tool 54 is configured to act as a fulcrum to control the
bending of the panel. The anvil tool 54 includes a leading edge 56
and an adjacent bottom surface 58. The leading edge 56 of the anvil
tool 54 acts as the fulcrum around which the panel is bent and the
adjacent bottom surface 58 holds the workpiece down against the
lower die 24 during the bending operation. The anvil tool 54 is an
interchangeable part and can be exchanged for anvil tools of other
configurations to accommodate body panels of varying
configurations.
[0030] The apparatus 20 has a vertical positioning mechanism 60
comprising apertured lower die tabs 62 fixed to the lower die part
24 of the bending machine 22 and apertured anvil arm tabs 64 fixed
to the arm 51 of the anvil assembly 50. Apertures formed in the
lower die tabs 62 are positioned to coaxially align with apertures
formed in the anvil arm tabs 64 when the anvil assembly 50 is in
the lowered position and the lower end hemming machine 38 is in the
bending position. A tapered pin 74 of the vertical positioning
mechanism 60 is automatically driven axially through the aligned
apertures when the lower end hemming machine 38 is in the bending
position to lock the anvil assembly 50 to the lower die 24 of the
bending machine 22 as the bending machine 22 is bending the
workpiece. The tapered pin 70 is automatically withdrawn before the
lower end hemming machine 38 is withdrawn along the linear slide
46.
[0031] In other embodiments of the combination body panel bender
and hemmer apparatus such as the one shown at 20' in FIG. 19, the
vertical positioning mechanism may include a key 66 and keyway 68
arrangement instead of the pin lock mechanism described above. As
shown in FIG. 19, the key 66 is supported on the lower die part 24
of the bending machine 22 and the keyway 68 is supported under the
arm 51 of the anvil assembly 50. When the lower end hemming machine
38 is advanced to the bending position, the key 66 is received into
a complimentary shaped notch 69 in the keyway 68 to prevent any
relative vertical motion between the anvil tool 54 and the bending
machine 22. In FIG. 19, reference numerals with the designation
prime (') indicate alternative configurations of elements that
appear in FIGS. 1-17.
[0032] Side hemming machines 76 are positioned on either side of
the lower die 24 of the bending machine 22 in respective positions
to hem respective side edges of the workpiece 34 that will become
side seams of the finished body panel. Each side hemming machine 76
includes a pre-hem steel 78 and a final hem steel 80 that are
individually movable to a position engaging respective side edges
of the workpiece 34 to hem those edges. Each side hemming machine
76 also includes a hem steel drive unit 82 that is operatively
connected to the pre-hem and final hem steels 78, 80 of each side
hemming machine 76, respectively, to individually advance and
retract the steels 78, 80 for pre-hem and final hem operations.
[0033] Corner hemming machines 84 may be positioned adjacent the
side hemming machines 76 in respective positions to initiate
hemming operations at corners of the body panel as is known in the
art.
[0034] In practice, a vehicle closure member such as tailgate can
be formed according to the invention by loading a pre-stamped metal
panel workpiece 34 onto the upper and lower die portions 24, 28 of
the bending machine 22 as shown in FIG. 1. The vacuum source is
then actuated to provide suction at the suction cups 32 to hold the
workpiece 34 securely in a position for bending and hemming as is
also shown in FIG. 1. The workpiece 34 may be loaded by a robot or
any other means known in the art. The anvil assembly drive 52 is
then actuated to rotate the anvil assembly 50 from the raised
position to the lowered position. The hemming machine drive 48 is
then actuated to advance the lower end hemming machine 38 and the
anvil assembly 50 to a position where the anvil tool 54 engages the
panel, i.e., the bending position as shown in FIGS. 2 and 3. Once
the lower end hemming machine 38 has advanced to the bending
position, the pin lock mechanism 60 is actuated to drive the
tapered pin 74 through the coaxially aligned apertures, 70 of the
lower die tabs 62 and the anvil arm tabs 64.
[0035] The bender drive mechanism 30 of the bending machine 22 is
then actuated to pivot the upper die portion 28 to the partially
closed position as shown in FIG. 4 which bends the panel workpiece
34 approximately 148.degree. to the partially closed position.
During the bending operation, the leading edge 56 of the anvil tool
54 acts as a fulcrum against which the panel workpiece 34 is bent.
After the apparatus 20 completes the bending operation, the pin
lock mechanism 60 is actuated to remove the tapered pin 74 from the
lower die tabs 62 and the anvil arm tabs 64. The hemming machine
drive 48 is then actuated to retract the lower end hemming machine
38 and anvil assembly 50 along the linear slide 46.
[0036] To begin the hemming operation, the anvil assembly drive 52
is actuated to rotate the anvil assembly 50 to the raised position
as shown in FIG. 6. The hemming machine drive 48 is then actuated
to advance the lower end hemming machine 38 to the hemming position
shown in FIGS. 8 and 9. The bender drive mechanism 30 is then
actuated to pivot the upper die portion 28 a final 12.degree. to
the closed position as shown in FIG. 6. The pre-hem steels of the
lower end hemming machine 38 and side hemming machines 76 are then
extended to pre-hem the panel workpiece 34. If present, the corner
hemming machines 84 may be then extended to initially hem
respective corners of the panel workpiece 34. The corner hemming
machines 84 may then be retracted from engagement with the panel
workpiece 34 and the final hem steels of the lower end and side
hemming machines 38, 76 are extended to accomplish a final hem of
the side and bottom end edges of the panel workpiece 34. The final
hem steels are then retracted from their respective positions in
engagement with the panel workpiece 34.
[0037] Following the completion of the hemming operation, the
bender drive mechanism 30 is actuated to pivot the upper die 28
portion away from the lower die 24 portion to the fully open
position. The hemming drive is actuated to retract the lower end
hemming machine 38 along the linear slide 46. The hemmed body panel
is then removed from the bending machine 22.
[0038] This description is intended to illustrate certain
embodiments of the invention rather than to limit the invention.
Therefore, it uses descriptive rather than limiting words.
Obviously, it's possible to modify this invention from what the
description teaches and one may practice the invention other than
as described.
* * * * *