Note: Descriptions are shown in the official language in which they were submitted.
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System And Method For Hemmina Comnonents
FIELD OF THE INVENTION
[0001] The present invention relates to a hemming system and method for
hemming
components. More specifically, the present invention relates to a hemming
system and
method which permits rapid change between respective setups to hem different
components
and which provides relatively short cycle times for the hemming operations.
BACKGROUND OF THE INVENTION
[00021 Systems for hemming the edges two or more metal components together to
form a
part are well known. Such systems are commonly used in the manufacture of
various
automotive body parts, such as doors, lift gates, hoods, etc., as well as in
the manufacture of
a variety of other manufactured goods.
[00031 When, for example, an automobile door is to be fabricated in a prior
art hemming
press, a previously stamped outer door panel is loaded onto an appropriately
shaped anvil
and the previously stamped inner door member is then placed atop the inside of
the outer
door panel and is held in place, with a clamp or other suitable mechanism,
with the edges of
the outer door panel and the inner door member overlying each other. The
hemming press is
then activated, moving an appropriately shaped first hemming beam through a
complex
motion, over and onto the anvil, to fold the edges of the outer door panel and
inner door
member over onto each other to a first extent, typically about forty-five
degrees.
[0004] The first hemming beam is then removed and a second appropriately
shaped
hemming beam is then moved through another complex motion, over and onto the
anvil, to
complete the hem by further folding the edges of the outer door panel and
inner door member
over onto each other to complete the part.
[0005] While hemming provides numerous advantages compared to other joining
techniques such as welding, hemming does suffer from some disadvantages. In
particular,
the setup positioning and alignment of the anvil, clamp and hemming beams and
the setup of
the shape and range of movements of these parts of the hemming machine are
time
consuming to accomplish and these actions must be performed each time it is
desired to
setup the machine to hem a different part. Thus, to be cost and/or time
effective, a large run
of parts needs to be hemmed during a run to amortize the setup costs for the
hemming
machine for that part. Therefore, hemming operations are not generally
susceptible to
versatile and/or just in time manufacturing processes.
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[00061 Further, the complex movement of the hemming beams, which move over and
onto
the components on the anvil to perform the initial hemming operation, and
again to perform
the second hemming operation to complete the part, results in a relatively
long minimum
cycle time for the hemming process.
[0007] It is desired to have a hemming system and/or method which allows for
the
relatively efficient change over of the system and method to hem different
parts and which
provides for a relatively short minimum cycle time.
SUMMARY OF THE INVENTION
[0008] It is an object of the present invention to provide a novel system and
method for
hemming components which obviates or mitigates at least one disadvantage of
the prior art.
[0009] According to a first aspect of the present invention, there is provided
a hemming
system for hemming the edges of two or more components, the system comprising:
a lift table
including a drive and a lift plate assembly, the drive operable to move the
lift plate assembly
through a fixed vertical stroke and operable to receive a tool platen assembly
comprising an
anvil, the lift plate assembly engaging the anvil through a lift path to move
the anvil vertically
through a stroke length corresponding to the fixed vertical stroke of the lift
plate, the lift table
being further operable to move a set of spacers into and out of the lift path
to selectably move
the anvil through the fixed stroke length from either a first or second
vertical position; a clamp
frame including a clamp carriage moveable vertically in the clamp frame, the
clamp carriage
receiving a clamp to engage and retain components to be hemmed which are
loaded onto the
anvil; and at least one beam assembly on the tool platen assembly, the at
least one beam
assembly including a mounting surface to which a preliminary hemming beam and
a final
hemming beam are mounted, one above the other, and the beam assembly being
operable to
move the mounting surface between a retracted position where the preliminary
hemming
beam and final hemming beam are distal the anvil and an operating position
wherein the
preliminary hemming beam and final hemming beam are adjacent the anvil such
that the
operative surface of one of the preliminary hemming beam and final hemming
beams is
positioned to engage the edge of the components as the anvil is moved
vertically upward.
[0010] According to another aspect of the present invention, there is provided
a method of
hemming at least two components comprising the steps of: (i) loading the
components to be
hemmed onto an anvil at a lowered preliminary hemming position and bringing a
complementary clamp into engagement with the components to retain the
components on the
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anvil; (ii) moving at least one beam mounting surface, to which a preliminary
hemming beam
and a final hemming beam are mounted one above the other, from a retracted
position distal
the anvil to an operating position adjacent the anvil; (iii) moving the anvil
upward, through a
fixed stroke length, from the lowered preliminary position to raised
preliminary position
whereby the edges of the components to be hemmed engage the operative surface
of the
preliminary hemming beam to perform a preliminary hemming operation; (iv)
returning the at
least one beam mounting surface to the retracted position; (v) moving the
anvil to a lowered
final hemming position, the vertical difference between the lowered
preliminary hemming
position and the lowered final hemming position corresponding to the vertical
distance
between the operative surface of the preliminary hemming beam and the
operative surface of
the final hemming beam on the beam mounting surface; (vi) moving the at least
one beam
mounting surface from the retracted position to the operating position; (vii)
moving the anvil
upward, through the fixed stroke length, from the lowered final hemming
position to a raised
final hemming position whereby the edges of the components to be hemmed engage
the
operative surface of the final hemming beam to complete the hemming operation;
(viii)
returning the at least one beam mounting surface to the retracted position;
and (ix) returning
the anvil to the lowered preliminary hemming and disengaging the clamp to
remove the
hemmed components.
[0011] The present invention provides a hemming system and method which
employs tool
platen assemblies comprising an anvil and one or more beam assemblies which
are
configured on the tool platen assembly and which tool platen assembly can be
removed and
replaced in the hemming system without the need for reconfiguration of the
tool platen
components. This allows for relatively rapid change over for the hemming
system to hem
different components. Further, the lift table of the hemming system includes a
lift plate which
moves the anvil through a predefined fixed vertical stroke, but the start and
end positions of
that fixed stroke length can be changed by inserting and removing a set of
spacers from the
anvil lift path. When the spacers are in the lift path, the lowered position
and the raised
position of the anvil are both higher than the corresponding lowered position
and raised
position when the spacers are removed from the lift path. The beam assemblies
on the tool
platen assembly include mounting surfaces to which both the preliminary
hemming beam and
the final hemming beams are mounted, one above the other, and the beam
assemblies
operate to move the hemming beams between a retracted position and a hemming
position.
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The lift table design, and the beam assemblies, combine to provide relatively
fast cycle times
for complete hemming operations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Preferred embodiments of the present invention will now be described,
by way of
example only, with reference to the attached Figures, wherein:
Figure 1 shows a rear view of a hemming system in accordance the present
invention;
Figure 2 shows perspective view of the side and top of a beam assembly
employed
with the hemming system of Figure 1;
Figure 3 shows a side cross section through a lift table of the hemming system
of
Figure 1 with the anvil in a lowered preliminary hemming position;
Figure 4 shows the lift table of Figure 3 with the anvil in a raised
preliminary hemming
position;
Figure 5 shows the lift table of Figure 3 with the anvil in a lowered final
hemming
position;
Figure 6 shows the lift table of Figure 3 with the anvil in a raised final
hemming
position; and
Figure 7 shows a top view of the lift table of Figure 3 with a tool platen
assembly
removed.
DETAILED DESCRIPTION OF THE INVENTION
[0013] A hemming system in accordance with the present invention is indicated
generally
at 20 in Figure 1. System 20 includes a lift table 24 and a clamp frame 28.
[0014] Lift table 24, which is best in Figures 3 through 7, removably receives
a tool platen
assembly 32 which includes an anvil 36 and at least one beam assembly 40, each
beam
assembly being appropriately mounted, as described below, to a platen plate 44
which also
forms part of tool platen assembly 32.
[0015] Clamp frame 28 includes a clamp carriage 48 which can be moved
vertically along
clamp frame 28 by a clamp lift motor 52 via a clamp lift arm 56. In the
illustrated
embodiment, a pair of gas-charged counter balances 58 are also connected to
clamp
carriage 48 via a pair of chains 60 to counter balance the static weight of
clamp carriage 48.
[0016] Clamp carriage 48 is moved, by clamp lift motor 52 and clamp lift arm
56, between
an open position (not shown), wherein clamp carriage 48 is raised within clamp
frame 28 to
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allow hemmed parts to be removed from anvil 36 and un-hemmed components to be
loaded
onto anvil 36, and a closed position (shown in Figure 1) wherein clamp
carriage 48 is lowered
within clamp frame 28 so that hemming operations can be performed, as
described below, on
components loaded onto anvil 36.
[0017] Clamp carriage 48 further preferably includes a pair of locks 64 which
can engage
and disengage clamp frame 28 to lock clamp carriage 48 in the closed position
during
hemming operations and to release clamp carriage 48 when hemming operations
have been
completed, to allow clamp carriage 48 to return to the open position for
unloading and
loading.
[0018] A component clamp 68, complementary to anvil 36, is mounted to clamp
carriage
48 via two or more guide posts 70 and one or more pneumatic cylinders 72 or
any other
suitable means as will occur to those of skill in the art. Pneumatic cylinders
72 allow clamp
68 to be brought into, and maintained in, contact with components to be hemmed
which have
been loaded onto anvil 36, after clamp carriage 48 has been moved to the
nominal hemming
position. Preferably, clamp 68 is mounted to guide posts 70 and pneumatic
cylinders 72 with
quick release connections, to allow clamp 68 to be changed when tool platen
assembly 32 is
changed, as described below.
[0019] Each beam assembly 40, as shown in Figure 2, includes base 100 which is
mounted to platen plate 44 to affix beam assembly 40 in a desired position
with respect to
anvil 36. Each beam assembly 40 further includes a beam support member 104 to
which the
hemming beams 106 (shown in Figure 1) are mounted. The design of hemming beams
106
is well known and will not be further discussed herein.
[0020] Beam support member 104 is moveable, via a pneumatic cylinder 108 or
any other
suitable means as will occur to those of skill in the art, in the directions
indicated by arrow
112, with respect to base 100. When installed on platen plate 44, beam support
member 104
can be moved by cylinder 108 between a hemming position, wherein beam support
member
104 is adjacent anvil 36 to position the hemming beams 106 for hemming, and a
free position
wherein beam support member 104 is moved away from anvil 36 to allow anvil 36
to be
repositioned (as described below) and/or to allow the loading of un-hemmed
components or
unloading of hemmed parts from system 20. Suitable indexing features, such as
appropriate
stops (not shown), operate between beam support member 104 and base 100 to
define the
free position and the hemming position and limit the movement of beam support
member 104
between these positions.
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[0021] Referring now to Figures 3 through 7, lift table 24 is better seen. As
shown in
Figure 3, tool platen assembly 32 is installed onto table 24 via a set of
complementary
mounting features which, in this specific embodiment, comprise a pair of rails
120 that are
mounted to the upper surface of table 24 and a complementary pair of tracks
124 that are
mounted to the underside of platen plate 44. As is described in more detail
below, tool platen
assembly 32 can be removed from table 24 as a unit, along with beam assemblies
40 and
anvil 36, maintaining the setup spacing and alignment of beam assemblies 40
and anvil 36 to
allow for the relatively rapid change of system 20 from hemming one set of
components to
manufacture a first part to hemming another set of components to manufacture
another part.
As will be apparent to those of skill in the art, clamp 68 will also be
changed when tool platen
assembly 32 is changed.
[0022] All connections to pneumatic cylinders 108 or the like and to any
electronic sensors
or other components associated with tool platen assembly 32 are preferably of
a suitable
quick disconnect type, allowing for a tool platen assembly 32 for hemming a
first set of
components to be quickly and easily changed for a tool platen assembly 32 for
hemming a
second set of components.
[0023] Anvil 36 includes two or more posts 128 which extend through, and ride
in bushings
132 in, platen plate 44 to allow anvil 36 to be raised and lowered vertically
with respect to
platen plate 44. Anvil 36 further includes at least one, and preferably more
than one, lift
spacer 136 each of which extends through a complementary aperture 140 in
platen plate 44.
[0024] When anvil 36 is in the position illustrated in Figure 3, platen
assembly 32 can be
removed from lift table 24 by inserting a temporary spacer (not shown) between
anvil 36 and
platen plate 44, to maintain anvil 36 at a sufficient height such that lift
spacers 136 and posts
128 are disengaged from other components of lift table 24 (described below)
and then tracks
124 of tool platen assembly 32 can be slid on rails 120 out of lift table 24
and onto a suitable
support.
[0025] Similarly, another tool platen assembly 32 can be loaded, from a
suitable support
with its anvil 36 maintained at an appropriate height, onto lift table 24 by
sliding its tracks 124
onto rails 120 of lift table 24. Once the tool platen assembly 32 is
positioned with posts 128
and lift spacers 136 properly positioned with respect to the other components
of lift table 24,
as described below, the temporary spacer holding up anvil 36 can be removed.
Any required
pneumatic, electrical or other connections are also established between lift
table 24 and
devices on tool platen assembly 32.
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[0026] In most circumstances, when a tool platen assembly 32 is removed and
replaced
with another tool platen assembly 32, a corresponding exchange of the clamp 68
mounted to
clamp carriage 48 will also be performed. Assuming that the newly installed
tool platen 32
and clamp 68 have previously been set up and operated in system 20, then
hemming
operations can typically be commenced without requiring further setup or
alignment.
[0027] Lift table 24 includes a main lift system which comprises a main drive
member 144
which is rotated by a suitable drive motor 146 (shown in Figure 7). Main drive
member 144 in
turn rotates, via a link member 148, a first eccentric arm 152 about a pivot
156. As first
eccentric arm 152 is rotated by main drive member 144, another link member 160
results in
the synchronous rotation of a second eccentric arm 164 about a pivot 168.
[0028] Each of first eccentric arm 152 and second eccentric arm 164 are
connected to a
respective lift arm 172 and 176 which are, in turn, connected to a lift plate
assembly 180. As
will now be apparent to those of skill in the art, as main drive member 144 is
rotated through
ninety degrees in the direction indicated by the arrows in Figure 3, lift
plate assembly 180 is
moved from the lowered position shown in Figure 3 to the raised position shown
in Figure 4.
[0029] As will also now be apparent to those of skill in the art, while the
illustrated
embodiment includes two eccentric arms 152 and 164 and corresponding lift arms
172 and
176, depending upon the force required to be produced by lift plate assembly
180 to perform
hemming operations, lift table 24 can be constructed with more or fewer
eccentric arms and
corresponding lift arms, as desired.
[0030] Lift plate assembly 180 includes a lift plate 188 and the upper ends of
lift arms 172
and 176 are attached to pivots 192 and 196 which are, in turn, also mounted to
lift plate
assembly 180. Two or more lift plate guide posts 200 are also mounted to lift
plate assembly
180 and guide posts 200 ride in bushings 204 attached to the frame 208 of lift
table 24 to
allow lift plate assembly 180 to move vertically with respect to lift table 24
while inhibiting
horizontal movement of lift plate assembly 180.
[0031] As should now be apparent to those of skill in the art, as main drive
member 144 is
rotated through the ninety degree revolution between the position illustrated
in Figure 3 and
the position illustrated in Figure 4, lift arms 172 and 176 move upward,
moving lift plate
assembly 180 from the lowered position, illustrated in Figure 3, to the raised
position
illustrated in Figure 4.
[0032] When lift plate assembly 180 is in the lowered position shown in Figure
3, anvil 36
is supported by lift spacers 136 which rest on an anvil support 210. Lift
spacers 136 thus
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support anvil 36 such that a slight gap exists between the bottoms of posts
128 and a set of
spacers 212 atop lift plate 188. As lift plate 188 is moved upwards with lift
plate assembly
180, lift plate 188 raises spacers 212 which, in turn, abut the bottom of
posts 128 to raise
anvil 36 from the lowered position, illustrated in Figure 3, to the raised
position illustrated in
Figure 4.
[0033] The position of anvil 36 in Figure 3 corresponds to the lowered
position of the
preliminary hemming operation while the position of anvil 36 is Figure 4
corresponds to the
raised hemming position of the preliminary hemming operation.
[0034] The resulting movement of anvil 36 from the lowered hemming position of
Figure 3
to the raised hemming position of Figure 4 will move components on anvil 36
vertically (along
with clamp 68) with respect to hemming beams 106 installed on beam support
members 40
on tool platen assembly 32.
[0035] In the present invention, the preliminary and final hemming beams are
mounted,
one above the other, on mounting surface 104 of beam support units 40.
Accordingly,
assuming that the preliminary hemming beam is mounted uppermost on beam
support
surfaces 104 and assuming that the beam mounting surfaces 104 have been moved
to their
operative position, in toward anvil 36, then the movement of anvil 36 and
clamp 68 from the
lowered position of Figure 3 to the raised hemming position of Figure 4 will
bring the edges of
the components to be hemmed into contact with the preliminary hemming beam and
the
edges of the components will be preliminarily folded to about forty five
degrees.
[0036] After the preliminary hemming operation has been performed, main drive
member
144 continues to rotate through another ninety degrees, as indicated by the
arrows in Figure
4, and lift arms 172 and 176 move downward, moving lift plate assembly 180 and
anvil 36
from the raised hemming position illustrated in Figure 4, toward the lowered
final hemming
position shown in Figure 5.
[0037] As lift plate assembly 180 moves down, the mounting surfaces 104 of
beam
support units 40 are moved to a retracted position, away from anvil 36 to
allow the height of
anvil 36 and clamp 68 to be changed, as described below. Also, as lift plate
assembly 180
continues to move down, anvil 36 is supported by lift spacers 136 and anvil
support 210.
When the load is off of spacers 212, spacers 212 are moved laterally (to the
right in the
illustrated configuration) to remove them from the lift path through posts 128
as shown in
Figures 5 and 6. Specifically, as best seen in Figure 7 spacers 212 are
mounted to a shuttle
frame 216 which can be moved laterally, between the position shown in Figures
3 and 4 and
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the position shown in Figures 5 and 6, by an actuator linkage 220, operated by
a pneumatic
cylinder (not shown) or other suitable actuator.
[0038] Once spacers 212 have been moved to the position shown in Figures 5 and
6,
wherein spacers 212 are adjacent posts 128, main drive member 144 continues to
rotate to
the position shown in Figure 5 and anvil support 210 is lowered and posts 128
abut lift plate
188. Anvil support 210 is lowered by a pneumatic cylinder 224, or the like,
and linkage 228
and anvil 36 and clamp 68 are in the lowered final hemming position of Figure
5.
[0039] To perform the final hemming operation, beam mounting surfaces 104 are
moved
to their operative position, in toward anvil 36 and, at this point, main drive
member 144 is
rotated counter clockwise (in the illustrated configuration) through ninety
degrees and lift arms
172 and 176 move upward. The shortened lift path between lift plate 188 and
anvil 36 (now
comprising just posts 128) results in anvil 36 moving from the lowered final
hemming position
of Figure 5 to the raised final hemming position of Figure 6.
[0040] When the final hemming operation is complete, main drive member 144 is
rotated
counter clockwise another ninety degrees from the position shown in Figure 6
and anvil
support 210 is raised to support anvil 36 and clamp 68. As main drive member
144 continues
to rotate, a clearance is opened between the bottoms of posts 128 and lift
plate 188 and
spacers 212 are moved into this clearance to again place them in the lift
path. When spacers
212 are in place, anvil support 210 is lowered and table 24 is again in the
lowered preliminary
hemming position of Figure 3.
[0041] At this point, beam mounting surfaces 104 are moved to their retracted
position,
locks 64 are released and clamp carriage 48 and clamp 68 are lifted in frame
28. The
completed hemmed part can then be removed from anvil 36, by an operator, robot
or any
other suitable means and the next set of components to be hemmed can be loaded
onto anvil
36 and the method described above can be performed again.
[0042] As should now be apparent, while lift table 24 has a fixed stroke
through which lift
plate assembly 180 is raised, by moving spacers 212 into and out of the lift
path between lift
plate 188 and posts 128, anvil 36 and clamp 68 can be lifted by this fixed
stroke between two
different sets of positions: between a lowered preliminary hemming position
(Figure 3) and a
raised preliminary hemming position (Figure 4); and between a lowered final
hemming
position (Figure 5) and a raised final hemming position (Figure 6).
[0043] The stroke length between the lowered preliminary hemming position and
the
raised preliminary hemming position is the same as the stroke length between
the lowered
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final hemming position and the raised final hemming position, the stroke
length in each case
corresponding to the range through which lift plate assembly 180 is moved by
lift arms 172
and 176.
[0044] Further, the distance between the lowered preliminary hemming position
and the
lowered final hemming position and the distance between the raised preliminary
hemming
position and the raised final hemming position each correspond to the height
of spacers 212
and to the spacing between the operative surfaces of the preliminary hemming
beam 106 and
the final hemming beam 106 on beam support surface 104.
[0045] After loading an appropriate platen assembly 32 and corresponding clamp
68 onto
lift table 24, when lift table 24 is in the lowered preliminary hemming
position of Figure 3, an
embodiment of the method of the present invention which executes a complete
hemming
operation cycle comprises the following steps:
(i) the components to be hemmed are loaded onto anvil 36;
(ii) clamp carriage 48 is moved down frame 28 until clamp 68 is brought into
engagement with the loaded components and locks 64 are extended to lock clamp
carriage 48 in place;
(iii) beam support surfaces 104 on beam assemblies 40 are moved in towards
anvil
36 to bring the hemming beams 106 to their operative position;
(iv) drive member 144 moves through a ninety degree revolution raising lift
plate
assembly 180 and thus raising anvil 36 up from the lowered preliminary hemming
position
to the raised preliminary hemming position to bring the edges of the loaded
components
into contact with the preliminary hemming beams to perform a preliminary
hemming
operation;
(v) drive member 144 moves through a further ninety degree revolution lowering
lift
plate assembly 180 and anvil 36 toward the lowered preliminary hemming
position while
beam support surfaces 104 on beam assemblies 40 are moved out away from anvil
36 to
return the hemming beams 106 to their retracted position;
(vi) as lift plate assembly 180 is lowered, anvil 36 is supported by anvil
support 210
and shuttle frame 216 is moved laterally to move spacers 212 out of the lift
path of lift
plate assembly 188. As drive member 144 completes its ninety degree
revolution, anvil
support 210 is lowered to lower anvil 36 and clamp 68 to the lowered final
hemming
position;
(vii) beam support surfaces 104 on beam assemblies 40 are moved in towards
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anvil 36 to bring the hemming beams 106 to their operative position;
(viii) drive member 144 moves through a ninety degree rotation in the opposite
direction to the rotations of (iv) and (v), raising lift plate assembly 180
and thus raising
anvil 36 up from the lowered final hemming position to the raised final
hemming position
to bring the edges of the loaded components into contact with the final
hemming beams to
complete the hemming operation;
(ix) drive member 144 moves through a further ninety degree revolution in the
opposite direction to the rotations of (iv) and (v), lowering lift plate
assembly 180 and anvil
36 toward the lowered preliminary hemming position. Anvil support 210 is
lifted to support
anvil 36 and shuttle frame 216 is moved to bring spacers 212 into the lift
path of lift plate
assembly 180. Beam support surfaces 104 on beam assemblies 40 are moved out
away
from anvil 36 to return the hemming beams 106 to their retracted position;
(x) locks 64 are released and clamp carriage 48 and clamp 68 are lifted; and
(xi) the completed part is removed from anvil 36 by any suitable means.
[0046] As will be apparent, at the completion of step (xi), the method can
recommence at
step (i) to hem the next set of components.
[0047] In the discussion above, the preliminary hemming beam 106 is mounted
above the
final hemming beam 106 on beam mounting surfaces 104 of beam assemblies 40
such that
the higher raised position (Figure 4) that anvil 36 achieves corresponds to a
raised
preliminary hemming position and the lower raised position (Figure 6) that
anvil 36 achieves
corresponds to a raised final hemming position. However, as will be apparent
to those of skill
in the art, the present invention is not so limited and the final hemming beam
can be mounted
on mounting surface 104 above the preliminary hemming beam if desired, in
which case the
higher raised position (Figure 4) will correspond to a raised final hemming
position and the
lower raised position (Figure 6) will correspond to a raised preliminary
hemming position, with
appropriate corresponding changes made to steps (i) through (xi) described
above.
[0048] The hemming system and method of the present invention provides
numerous
advantages over the prior art. Specifically, it is contemplated that the
present invention can
provide much faster cycle times than have been generally available with the
prior art. With
the particular illustrated embodiment of the invention, total cycle times of
less than fifteen
seconds have been achieved to hem an automobile door.
[0049] Further, by employing tool platen assemblies 32 and corresponding
clamps 68, tool
change times are significantly reduced as the positioning and alignment of
clamp 36 and
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beam assemblies 40 need only be performed once to configure a tool platen
assembly. Once
the initial set up and configuration has been performed for a tool platen
assembly 32, that tool
platen assembly 32 and its corresponding clamp 68 can be removed for storage,
when not
needed, and can be reloaded onto system 20, when needed again, in only a few
minutes as
the positioning and alignment of anvil 36 and beam assemblies 40 does not
change when a
tool platen assembly 32 is removed from and replaced on system 20.
[0050] The present invention provides a hemming system and method which
employs tool
platen assemblies comprising an anvil and one or more beam assemblies which
are
configured on the tool platen assembly and which tool platen assembly can be
removed and
replaced in the hemming system without the need for reconfiguration of the
tool platen
components. This allows for relatively rapid change over for the hemming
system to hem
different components. Further, the lift table of the hemming system includes a
lift plate which
moves the anvil through a predefined constant vertical stroke, but the start
and end positions
of that constant stroke length can be changed by inserting and removing a set
of spacers
from the anvil lift path. When the spacers are in the lift path, the lowered
position and the
raised position of the anvil are both higher than the corresponding lowered
position and
raised position when the spacers are removed from the lift path. The beam
assemblies on
the tool platen assembly include mounting surfaces to which both the
preliminary hemming
beam and the final hemming beams are mounted, one above the other, and the
beam
assemblies operate to move the hemming beams between a retracted position and
a
hemming position. The lift table design, and the beam assemblies, combine to
provide
relatively fast cycle times for complete hemming operations.
[0051] The above-described embodiments of the invention are intended to be
examples of
the present invention and alterations and modifications may be effected
thereto, by those of
skill in the art, without departing from the scope of the invention which is
defined solely by the
claims appended hereto.
