U.S. patent application number 11/731649 was filed with the patent office on 2008-10-02 for wheelhouse robotic roller hemming.
This patent application is currently assigned to Hirotec America, Inc.. Invention is credited to James B. Toeniskoetter.
Application Number | 20080236236 11/731649 |
Document ID | / |
Family ID | 39792004 |
Filed Date | 2008-10-02 |
United States Patent
Application |
20080236236 |
Kind Code |
A1 |
Toeniskoetter; James B. |
October 2, 2008 |
Wheelhouse robotic roller hemming
Abstract
A robotic roller hemming apparatus includes a mounting member
having a face for operative connection of the mounting member to a
multi-axis controllable robotic arm, and a bracket extending from
the face. A tracking roller is mounted on the bracket. A slide
plate is operatively connected to the bracket and slidable relative
to the bracket. A hemming roller is operatively connected to the
slide plate proximate the tracking roller for roller hemming nested
metal panels therebetween the hemming and tracking rollers. A slide
actuator connects the bracket and the slide plate for moving the
hemming roller toward and away from the tracking roller.
Inventors: |
Toeniskoetter; James B.;
(Rochester Hills, MI) |
Correspondence
Address: |
Christopher J. Fildes;Fildes & Outland, P.C.
Suite 2, 20916 Mack Avenue
Grosse Pointe Woods
MI
48236
US
|
Assignee: |
Hirotec America, Inc.
|
Family ID: |
39792004 |
Appl. No.: |
11/731649 |
Filed: |
March 30, 2007 |
Current U.S.
Class: |
72/220 |
Current CPC
Class: |
B21D 39/023 20130101;
B21D 39/021 20130101 |
Class at
Publication: |
72/220 |
International
Class: |
B21D 7/022 20060101
B21D007/022 |
Claims
1. A robotic roller hemming apparatus comprising: a mounting member
including face for operative connection of the mounting member to a
multi-axis controllable robotic arm, and a bracket extending from
said face; a tracking roller mounted on said bracket; a slide plate
operatively connected to said bracket and slidable relative to said
bracket; a hemming roller operatively connected to said slide plate
proximate said tracking roller for roller hemming nested metal
panels therebetween said hemming and tracking rollers; and a slide
actuator connecting said bracket and said slide plate for moving
said hemming roller toward and away from said tracking roller.
2. The robotic roller hemming apparatus of claim 1, including a
linkage assembly operatively connected to said mounting member and
said hemming roller for pivoting said hemming roller relative to
said mounting member; and a pivot actuator for actuating said
linkage assembly to pivot said hemming roller.
3. The robotic roller hemming apparatus of claim 2, wherein said
linkage assembly includes: a pivot bar having first and second
opposite ends, said pivot bar first end being pivotally connected
to said slide plate and said pivot bar second end being operatively
connected to said hemming roller; a link bar having first and
second opposite ends, said link bar first end being pivotally
attached to said pivot bar second end adjacent said hemming roller;
and a bell crank arm having first and second opposite ends, said
bell crank arm first end being pivotally connected to said link bar
second end and said bell crank arm second end being pivotally
connected to said pivot actuator; said bell crank arm being
pivotally connected to said slide plate intermediate said bell
crank arm first and second ends.
4. The robotic roller hemming apparatus of claim 3, including a
stop mounted to said slide plate, said stop limiting the pivotal
movement of said pivot bar.
5. The robotic roller hemming apparatus of claim 2, wherein said
pivot actuator is mounted on said slide plate.
6. The robotic roller hemming apparatus of claim 1, wherein said
slide actuator is mounted on said mounting member bracket.
7. The robotic roller hemming apparatus of claim 1, wherein said
mounting member bracket includes a linear track, and said slide
plate is operatively engaged with said linear track and slidable
along said linear track.
8. The robotic roller hemming apparatus of claim 7, wherein said
linear track includes a pair of rails, and said slide plate
includes a pair of bearing blocks engaged with said pair of
rails.
9. A robotic roller hemming system comprising: a first multi-axis
controllable robotic arm having an end effecter that carries a
hemming anvil; a second multi-axis controllable robotic arm having
a roller hemming head at an end thereof, said roller hemming head
including a tracking roller and a multi-positional hemming roller
capable of performing both pre-hemming and final hemming
operations; said hemming roller being adjustable between
pre-hemming and final hemming positions and cooperable with said
tracking roller and anvil to pre-hem and final hem a workpiece;
wherein said hemming roller performs pre-hemming and subsequent
final hemming of said workpiece sequentially along a single hemming
path.
10. The robotic roller hemming system of claim 9, wherein said
hemming roller is positionable about an edge of said workpiece on
one side of the workpiece; and said anvil is positionable adjacent
the workpiece about a side opposite said hemming roller.
11. The robotic roller hemming system of claim 9, wherein said
first robotic arm end effecter comprises a robotic tool exchange
unit for interchanging said anvil with at least one alternative
anvil.
12. The robotic roller hemming system of claim 11, including an
anvil storage unit for holding said at least one alternative
hemming anvil.
13. The robotic roller hemming system of claim 9, wherein said
anvil includes an attachment device for temporary attachment of
said anvil to said workpiece.
14. The robotic roller hemming system of claim 13, wherein said
attachment device includes an arrangement of vacuum cups.
15. The robotic roller hemming system of claim 9, wherein said
first robotic arm includes a location unit for positioning said
anvil relative to a workpiece.
16. The robotic roller hemming system of claim 9, wherein said
hemming roller includes an indexing feature cooperable with an edge
of said anvil that allows for indexing of said hemming roller
between pre-hemming and final hemming positions.
17. The robotic roller hemming system of claim 9, wherein said
roller hemming head includes a servo positioner for adjusting the
hemming roller between various pre-hemming and final hemming
angular positions relative to said anvil.
18. The robotic roller hemming system of claim 9, wherein said
roller hemming head includes an actuator for adjusting the hemming
roller between various pre-hemming and final hemming angular
positions relative to said anvil.
19. The robotic roller hemming system of claim 9, wherein said
tracking roller is engagable with said anvil to aide in guiding
said roller hemming head along said anvil.
20. The robotic roller hemming system of claim 9, wherein said
roller hemming head includes a slide unit for compressing said
workpiece and said anvil between said hemming roller and said
tracking roller.
21. The robotic roller hemming system of claim 20, wherein said
slide unit linearly moves said hemming roller to adjust the
distance between said hemming roller and said tracking roller.
22. A method for robotic roller hemming comprising the steps of:
providing a first multi-axis controllable robotic arm having an end
effecter that carries a hemming anvil having a hemming surface and
a tracking surface; providing a second multi-axis controllable
robotic arm having a roller hemming head at an end thereof, said
roller hemming head including a hemming roller adjustable between
pre-hemming and final hemming positions and a tracking roller
proximate said hemming roller; employing said first robotic arm to
position said anvil hemming surface adjacent a workpiece; adjusting
said hemming roller to said pre-hemming position; employing said
second robotic arm to position said roller hemming head relative to
said workpiece and said anvil such that said tracking roller
contacts said anvil tracking surface and said hemming roller
engages said workpiece; employing said second robotic arm to move
said roller hemming head along said anvil such that said tracking
roller follows said anvil tracking surface and said hemming roller
pre-hems said workpiece; adjusting said hemming roller to said
final hemming position; and employing said second robotic arm to
move said roller hemming head along said anvil such that said
tracking roller follows said anvil tracking surface and said
hemming roller final hems said workpiece.
23. The method of claim 22, wherein a path followed by said hemming
roller during pre-hemming is also followed by said hemming roller
during final hemming.
24. The method of claim 23, wherein during final hemming, said
hemming roller follows said path in the same direction of travel as
during pre-hemming.
25. The method of claim 23, wherein during final hemming, said
hemming roller follows said path in a reverse direction relative to
a direction of travel followed during pre-hemming.
26. The method of claim 22, further including the step of: after
said first robotic arm positions said anvil hemming surface
adjacent said workpiece, temporarily attaching said anvil to said
workpiece to stabilize said anvil relative to said workpiece.
27. The method of claim 22, wherein said roller hemming head
includes a slide unit for engaging and disengaging said tracking
roller with said anvil tracking surface and said hemming roller
with said workpiece; the method further including the steps of
actuating said slide unit to engage said tracking roller with said
anvil tracking surface and said hemming roller with said workpiece
prior to pre-hemming; and actuating said slide unit to disengage
said tracking roller with said anvil tracking surface and said
hemming roller with said workpiece after final hemming.
28. The method of claim 22, further comprising the steps of: after
said hemming roller final hems said workpiece, employing said
second robotic arm to move said roller hemming head away from said
workpiece; and employing said first robotic arm to move said anvil
away from said workpiece.
Description
TECHNICAL FIELD
[0001] This invention relates to hemming of a bent edge of one or
more preformed metal panels to form a hemmed joint or closed panel,
and more particularly to an apparatus, system, and method for
robotic roller hemming.
BACKGROUND OF THE INVENTION
[0002] It is known in the art relating to hemming of metal panels
that roller hemming apparatus can be used to hem the edges of the
metal panels forming automotive parts such as door panels, hood
panels, and decklid panels.
[0003] Conventionally, a hemming apparatus may be mounted to a
multi-axis controllable robot and may include a hem roller carried
by a support. The conventional hemming apparatus is adapted for
hemming a bent edge portion of a workpiece, such as a door panel,
positioned on a hemming die, by rotating the hem roller under
pressure along the bent portion. The conventional roller type
hemming apparatus can thus be used for continuous hemming along the
contour of the edge of the workpiece. This process, however,
requires moving the workpiece to the hemming die and positioning
the workpiece in the die.
[0004] Further, it is known to use a portable hemming die apparatus
to hem a vehicle wheelhouse area. Such a portable hemming apparatus
includes a hemming die set and may be mounted to a robot arm. The
robot arm may then move the hemming die set to a workpiece to hem
the workpiece. The hemming die, however, may be heavy and bulky to
move. Also, each hemming die is specific to the shape and design of
a certain workpiece. Hence, the hemming die must be changed when a
different workpiece is introduced into a system.
SUMMARY OF THE INVENTION
[0005] The present invention provides a robotic roller hemming
apparatus, system, and method that utilizes a single roller head
for pre-hemming and final hemming that can compensate for various
material thicknesses. The apparatus, system, and method requires
just one programmed robot path to perform both pre-hemming and
final hemming, thereby allowing for pre-hemming and final hemming
along one path without the need to remove the roller head from the
workpiece. The present apparatus, system, and method further allows
for the hemming of a plurality of differently shaped workpieces
using a single tooling fixture, and allows for adjustment of the
pressure on the roller head to conform with various hemming product
requirements.
[0006] More particularly, the present invention provides a dual
robot system and method in which one robot carries a lightweight
anvil and a second robot carries a universal roller hemming head
apparatus including a hemming roller for both pre-hemming and final
hemming of a workpiece such as a vehicle wheelhouse.
[0007] In one embodiment, a robotic roller hemming apparatus in
accordance with the invention includes a mounting member having a
face for operative connection of the mounting member to a
multi-axis controllable robotic arm, and a bracket extending from
the face. A tracking roller is mounted on the bracket. A slide
plate is operatively connected to the bracket and slidable relative
to the bracket. A hemming roller is operatively connected to the
slide plate proximate the tracking roller for roller hemming nested
metal panels therebetween the hemming and tracking rollers. A slide
actuator connects the bracket and the slide plate for moving the
hemming roller toward and away from the tracking roller.
[0008] The robotic roller hemming apparatus may further include a
linkage assembly operatively connected to the mounting member and
the hemming roller for pivoting the hemming roller relative to the
mounting member, and a pivot actuator for actuating the linkage
assembly to pivot the hemming roller. The linkage assembly may
include a pivot bar having first and second opposite ends, the
pivot bar first end being pivotally connected to the slide plate
and the pivot bar second end being operatively connected to the
hemming roller; a link bar having first and second opposite ends,
the link bar first end being pivotally attached to the pivot bar
second end adjacent the hemming roller; and a bell crank arm having
first and second opposite ends, the bell crank arm first end being
pivotally connected to the link bar second end and the bell crank
arm second end being pivotally connected to the pivot actuator. The
bell crank arm is pivotally connected to the slide plate
intermediate its first and second ends. A stop may be mounted to
the slide plate. The stop limits the pivotal movement of the pivot
bar.
[0009] The pivot actuator may be mounted on the slide plate. The
slide actuator may be mounted on the mounting member bracket. The
mounting member bracket may include a linear track, and the slide
plate is operatively engaged with the linear track and slidable
along the linear track. The linear track may include a pair of
rails, and the slide plate may include a pair of bearing blocks
engaged with the pair of rails.
[0010] A dual-robot, robotic roller hemming system in accordance
with the invention includes a first multi-axis controllable robotic
arm having an end effecter that carries a hemming anvil. The system
also includes a second multi-axis controllable robotic arm having a
roller hemming head at an end thereof. The roller hemming head
includes a tracking roller and a multi-positional hemming roller
capable of performing both pre-hemming and final hemming
operations. The hemming roller is adjustable between pre-hemming
and final hemming positions and cooperable with the tracking roller
and anvil to pre-hem and final hem a workpiece. The hemming roller
performs pre-hemming and subsequent final hemming of the workpiece
sequentially along a single hemming path.
[0011] The hemming roller may be positionable about an edge of the
workpiece on one side of the workpiece, and the anvil may be
positionable adjacent the workpiece about a side opposite the
hemming roller. The first robotic arm may include a location unit
for positioning the anvil relative to a workpiece. The first
robotic arm end effecter may include a robotic tool exchange unit
for interchanging the anvil with at least one alternative anvil.
The system may also include an anvil storage unit for holding the
at least one alternative hemming anvil. The anvil may include an
attachment device for temporary attachment of the anvil to the
workpiece. The attachment device may include an arrangement of
vacuum cups.
[0012] The hemming roller may include an indexing feature
cooperable with an edge of the anvil that allows for indexing of
the hemming roller between pre-hemming and final hemming positions.
The roller hemming head may include a servo positioner for
adjusting the hemming roller between various pre-hemming and final
hemming angular positions relative to the anvil. Alternatively, the
roller hemming head may include an actuator for adjusting the
hemming roller between various pre-hemming and final hemming
angular positions relative to the anvil.
[0013] The tracking roller may be engagable with the anvil to aide
in guiding the roller hemming head along the anvil. The roller
hemming head may include a slide unit for compressing the workpiece
and the anvil between the hemming roller and the tracking roller.
The slide unit may linearly move the hemming roller to adjust the
distance between the hemming roller and the tracking roller.
[0014] A method for robotic roller hemming in accordance with the
invention includes providing a first multi-axis controllable
robotic arm having an end effecter that carries a hemming anvil
having a hemming surface and a tracking surface. A second
multi-axis controllable robotic arm having a roller hemming head at
an end thereof is also provided. The roller hemming head includes a
hemming roller adjustable between pre-hemming and final hemming
positions and a tracking roller proximate the hemming roller. The
first robotic arm is employed to position the anvil hemming surface
adjacent a workpiece. The hemming roller is adjusted to the
pre-hemming position. The second robotic arm is employed to
position the roller hemming head relative to the workpiece and the
anvil such that the tracking roller contacts the anvil tracking
surface and the hemming roller engages the workpiece. The second
robotic arm is employed to move the roller hemming head along the
anvil such that the tracking roller follows the anvil tracking
surface and the hemming roller pre-hems the workpiece. The hemming
roller is adjusted to the final hemming position. The second
robotic arm is employed to move the roller hemming head along the
anvil such that the tracking roller follows the anvil tracking
surface and the hemming roller final hems the workpiece.
[0015] After the first robotic arm positions the anvil hemming
surface adjacent the workpiece, the anvil may be temporarily
attached to the workpiece to stabilize the anvil relative to the
workpiece.
[0016] A path followed by the hemming roller during pre-hemming may
also be followed by the hemming roller during final hemming. In
other words, the pre-hemming and final hemming paths may be
essentially identical. During final hemming, the hemming roller may
follow the hemming path in the same direction of travel as during
pre-hemming. Alternatively, the hemming roller may follow the
hemming path in a reverse direction relative to a direction of
travel followed during pre-hemming.
[0017] The roller hemming head may include a slide unit for
engaging and disengaging the tracking roller with the anvil
tracking surface and the hemming roller with the workpiece. The
slide unit may be actuated to engage the tracking roller with the
anvil tracking surface and the hemming roller with the workpiece
prior to pre-hemming. The slide unit may also be actuated to
disengage the tracking roller with the anvil tracking surface and
the hemming roller with the workpiece after final hemming.
[0018] After the hemming roller final hems the workpiece, the
second robotic arm may be employed to move the roller hemming head
away from the workpiece, and the first robotic arm may be employed
to move the anvil away from the workpiece.
[0019] These and other features and advantages of the invention
will be more fully understood from the following detailed
description of the invention taken together with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In the drawings:
[0021] FIG. 1 is a perspective view robotic roller hemming
apparatus in accordance with the invention for pre-hemming and
final hemming nested metal panels;
[0022] FIG. 2 is a side view of the robotic roller hemming
apparatus of FIG. 1;
[0023] FIG. 3 is a schematic view of an alternative embodiment of a
robotic roller hemming apparatus in accordance with the invention
in a pre-hemming position relative to an anvil and a workpiece, and
a final hemming position partially shown in phantom;
[0024] FIG. 4 is an environmental view of a robotic roller hemming
system in accordance with the invention including a multi-axis
controllable robotic arm having the robotic roller hemming
apparatus at an end thereof;
[0025] FIG. 5 is a schematic view of another multi-axis
controllable robotic arm having an end effecter that carries a
hemming anvil; and
[0026] FIG. 6 is a side view of the robotic roller hemming
apparatus in a final hemming position relative to an anvil and a
workpiece, and a pre-hemming position shown in phantom.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Referring now to the drawings in detail, numeral 10
generally indicates a robotic roller hemming apparatus in
accordance with the invention. Turning first to FIGS. 1 and 2, the
robotic roller hemming apparatus 10 includes a mounting member 12
having a face 14 for operative connection of the mounting member 12
to a multi-axis controllable robotic arm, and a bracket 16
extending from the face 14. A rotatable tracking roller 18 is
mounted on the bracket 16. A slide plate 20 is operatively
connected to the bracket 16 and slidable relative to the bracket. A
multi-positional, rotatable hemming roller 22 is operatively
connected to the slide plate 20 proximate the tracking roller 18
for roller hemming nested metal panels therebetween the hemming and
tracking rollers. The hemming roller 22 is cooperable with the
tracking roller 18 to perform sequential hemming operations along a
single hemming path. Due to its multi-position capability, the
hemming roller 22 can also perform both pre-hemming and final
hemming operations by adjusting the angular orientation of the
hemming roller 22 relative to the tracking roller 18. A slide
actuator 24 connects the bracket 16 and the slide plate 20 for
moving the hemming roller 22 toward and away from the tracking
roller 18. The slide actuator 24 may include a piston 25
operatively connected to a flange 21 of the slide plate 20. The
slide actuator 24 may be pneumatically operated, hydraulically
operated, or similar.
[0028] In a specific embodiment, the robotic roller hemming
apparatus 10 may further include a linkage assembly 26 operatively
connected to the mounting member 12 and the hemming roller 22 for
pivoting the hemming roller relative to the mounting member. A
pivot actuator 28 actuates the linkage assembly 26 to pivot the
hemming roller 22, thereby adjusting the hemming roller 22 between
various pre-hemming and final hemming angular positions relative to
a workpiece. The pivot actuator 28 may be pneumatically operated,
hydraulically operated, or similar. The linkage assembly 26 may
include a pivot bar 30 having first and second opposite ends 32, 34
respectively. The pivot bar first end 32 is pivotally connected to
the slide plate 20 and the pivot bar second end 34 is operatively
connected to the hemming roller 22. For example, the hemming roller
22 may be rotatably mounted on a mount 36 via an axle 38, and the
mount 36 may be connected to the pivot bar 30. A stop 39 may be
mounted to the slide plate 20. The stop 39 limits the pivotal
movement of the pivot bar 30. The linkage assembly 26 further
includes a link bar 40 having first and second opposite ends 42, 44
respectively. The link bar first end 42 is pivotally attached to
the pivot bar second end 34 adjacent the hemming roller 22. The
linkage assembly 26 also includes a bell crank arm 46 having first
and second opposite ends 48, 50 respectively. The bell crank arm
first end 48 is pivotally connected to the link bar second end 44.
The bell crank arm second end 50 is pivotally connected to the
pivot actuator 24. For example, the bell crank arm second end 50
may be pivotally connected to an end of a piston 52 of the pivot
actuator 24. The bell crank arm 46 is also pivotally connected to
the slide plate 20 intermediate the bell crank arm first and second
ends 48, 50. It should be understood, however, that the linkage
assembly 26 may have a different mechanical structure for pivoting
the hemming roller 22. The hemming roller 22 may be pivoted by
other mechanical or electromechanical arrangements. For example,
the apparatus 10 may include a servo positioner for adjusting the
hemming roller 22 between various pre-hemming and final hemming
angular positions.
[0029] The pivot actuator 28 may be mounted on the slide plate 20
by a fastener 54 or similar. Therefore, the linkage assembly 26 and
pivot actuator 28 remain stationary relative to the slide plate 20
as the slide plate 20 moves relative to the mounting member 12. The
slide actuator 24 may be mounted on the mounting member bracket 16.
Hence, the slide actuator 24 is fixed relative to the mounting
member 12.
[0030] The mounting member bracket 16 may include a linear track
56. The slide plate 20 is operatively engaged with the linear track
56 and slidable along the linear track. The linear track 56 may
include a pair of rails 58, and the slide plate 20 may include a
pair of bearing blocks 60 engaged with the pair of rails 58.
[0031] Turning to FIG. 3, in an alternative embodiment, a robotic
roller hemming apparatus 110 includes a mounting member 112 and
operatively connected tracking roller 118 and hemming roller 122.
The hemming roller may include an indexing portion 180 that is
cooperable with an edge of an anvil 168 that allows for indexing of
the hemming roller 122 between pre-hemming and final hemming
positions. In FIG. 3, the hemming roller 122 is shown in the
pre-hemming position relative to a workpiece 174 and anvil 168. The
final hemming position of the hemming roller 122 is shown in
phantom. The roller hemming apparatus 110 may some of the other
features described in the first embodiment. For example, the roller
hemming apparatus 110 may include a linear rail 156 mounted on the
mounting member 112, and a slide plate 120 including bearing blocks
160 that are engaged with the linear rail 156. The hemming roller
122 may be operatively connected to the slide plate 120, and
movement of the slide plate 120 adjusts the distance between the
hemming roller 122 and tracking roller 118.
[0032] With reference to FIGS. 1, 4, and 5, the robotic roller
hemming apparatus 10 may be used in a dual-robot roller hemming
system 62. The robotic roller hemming system 62 includes a first
multi-axis controllable robotic arm 64 having an end effecter 66
that carries a hemming anvil 68. The end effecter 66 may be a
robotic tool exchange unit that engages and carries the anvil 68
and allows for easy interchange of the anvil 68 with at least one
alternative anvil 70. Interchange of the anvil 68 for an
alternative anvil 70 allows the system 62 to hem various workpieces
of differing size and shape. The roller hemming system 62 may also
include an anvil storage unit 71 for holding the at least one
alternative hemming anvil 70. Each anvil 68, 70 may include a
nesting feature (not shown) that cooperates with features in the
anvil storage unit 71 to hold the anvils 68, 70 in the storage
unit. The anvil 68 may also include an attachment device 72 for
temporary attachment of the anvil to a workpiece 74. The attachment
device 72 may include an arrangement of vacuum cups. The vacuum
cups may be operated by a vacuum suction source that can be
activated to hold the anvil 68 to the workpiece 74 and deactivated
to release the anvil from the workpiece. The first robotic arm 64
may include a location unit 76 for positioning the anvil 68
relative to the workpiece 74. The location unit 76 may include a
vision system and/or a simple measuring system.
[0033] The robotic roller hemming system 62 also includes a second
multi-axis controllable robotic arm 78 has a roller hemming head,
such as the roller hemming apparatus 10, at an end thereof. The
second robotic arm 78 can manipulate the hemming apparatus 10 to
position the hemming roller 22 about an edge of the workpiece 74 on
one side of the workpiece, and the anvil 68 may be positionable
adjacent the workpiece about a side opposite the hemming roller
22.
[0034] The tracking roller 18 is engagable with the anvil 68 to
aide in guiding the roller hemming apparatus 10 along the anvil.
The slide plate 20 is linearly moveable to adjust the distance
between the hemming roller 22 and tracking roller 18, thereby
allowing for compression of the workpiece 74 and the anvil 68
between the hemming roller 22 and the tracking roller 18.
[0035] With reference now to FIGS. 1, 4, and 6, the anvil 68 may
include a tracking surface 82 and a hemming surface 84. The first
robotic arm 64 may be employed to position the anvil hemming
surface 84 adjacent the workpiece 74, such as along an edge of the
workpiece to be hemmed. After the first robotic arm 64 positions
the anvil hemming surface 84 adjacent the workpiece 74, the anvil
68 may be temporarily attached to the workpiece to stabilize the
anvil relative to the workpiece. For example, if the anvil 68
includes vacuum cups 72, a suction device may be activated so that
the vacuum cups 72 hold the anvil 68 against the workpiece 74.
[0036] The pivot actuator 28 may be activated to adjust the hemming
roller 22 into the pre-hemming position. In the pre-hemming
position, the hemming roller 22 may be at a 45.degree. angle
relative to the edge of the workpiece 74. Alternatively, the
hemming roller 22 may pre-hem the workpiece at 30.degree. and
60.degree. angles relative to the workpiece edge. The second
robotic arm 78 is employed to position the roller hemming head,
such as roller hemming apparatus 10, relative to the workpiece 74
and to the anvil 68 such that the tracking roller 18 contacts the
anvil tracking surface 82 and the hemming roller 22 engages the
workpiece 74. For example, the slide plate 20 may be actuated to
engage the tracking roller 18 with the anvil tracking surface 82
and to engage the hemming roller 22 with the workpiece 74 prior to
pre-hemming. The pressure the hemming roller 22 exerts on the
workpiece 74 can be adjusted by varying the amount of force exerted
on the slide plate 20 by the slide actuator 24.
[0037] When the tracking roller 18 and hemming roller 22 are
properly engaged, the second robotic arm 78 is employed to move the
roller hemming apparatus 10 along the anvil 68 such that the
tracking roller 18 follows the anvil tracking surface 82 and the
hemming roller 22 pre-hems the workpiece 74. Next, the hemming
roller 22 may be adjusted to the final hemming position. In the
final hemming position, the hemming roller 22 is at a 90.degree.
angle relative to the edge of the workpiece 74. The second robotic
arm 78 is then employed to move the roller hemming apparatus 10
along the anvil 68 such that the tracking roller 18 follows the
anvil tracking surface 82 and the hemming roller 22 final hems the
workpiece 74.
[0038] A path followed by the hemming roller 22 during the
pre-hemming stroke may also be followed by the hemming roller
during final hemming. In other words, the pre-hemming and final
hemming paths may be essentially identical. Likewise, the tracking
roller 18 may follow the same path along the anvil track surface 82
during pre-hemming and final hemming. Moreover, during final
hemming, the hemming roller 22 may follow the hemming path in the
same direction of travel as during pre-hemming. In this case, the
second robotic arm 78 may move the hemming roller 22 forward during
pre-hemming, return the hemming roller 22 to its starting position
by generally moving the hemming roller 22 in a reverse direction,
and then move the hemming roller 22 forward during final hemming.
Further, while moving the hemming roller 22 back to its starting
position after pre-hemming, the hemming apparatus 10 may adjust the
hemming roller 22 from its pre-hemming angular configuration to its
final hemming configuration.
[0039] Alternatively, for final hemming, the hemming roller 22 may
follow the hemming path in a reverse direction relative to a
direction of travel followed during pre-hemming. In this case, the
second robotic arm 78 moves the hemming roller 22 forward during
pre-hemming from a first location to a second location, and then
moves the hemming roller 22 in reverse during final hemming from
the second location back to the first location.
[0040] After the hemming roller 22 final hems the workpiece 74, the
slide plate 20 may be actuated to disengage the tracking roller 18
with the anvil tracking surface 82 and the hemming roller 22 with
the workpiece 74 after final hemming. More specifically, the slide
actuator 24 moves the slide plate 20 outwardly relative to the
mounting member 12 to increase the distance between the tracking
roller 18 and hemming roller 22. Finally, the second robotic arm 78
may be employed to move the roller hemming apparatus 10 away from
the workpiece 74, and the first robotic arm 64 may be employed to
move the anvil 68 away from the workpiece. If the anvil 68 has been
temporarily attached to the workpiece 74 by attachment device 72,
the attachment devices 72 are deactivated/released prior to the
first robotic arm 64 moving the anvil 68.
[0041] Although the invention has been described by reference to
specific embodiments, it should be understood that numerous changes
may be made within the spirit and scope of the inventive concepts
described. Accordingly, it is intended that the invention not be
limited to the described embodiments, but that it have the full
scope defined by the language of the following claims.
* * * * *