Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM FOR LOW-FORCE ROLL FOLDING
AND METHODS THEREOF
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent Application
No.
61/029,322 filed February 16, 2008, entitled SYSTEM FOR LOW-FORCE ROLL
FOLDING AND METHODS THEREOF, the entire contents of which is incorporated
herein for all purposes by this reference.
BACKGROUND OF THE INVENTION
Field of the Invention
100021 This invention relates, in general, to systems for low-force roll
folding, and more
particularly to devices which may be used for roll folding of sheets having
bend-
facilitating fold lines, and methods for their use.
Description of Related Art
[00031 Roll forming is a continuous bending operation in which a two-
dimensional sheet
of material, for example, sheet metal is passed through a series of rollers,
each
performing an incremental amount of bending, until a particular cross-
sectional profile of
a three-dimensional product or item is produced. A "flower pattern" represents
each
incremental cross-sectional profile from flat two-dimensional sheet metal to
ultimate
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cross-sectional profile of the three-dimensional product. Roll forming is
generally used to
produce objects formed of sheet metal having straight, longitudinal, and
parallel bends.
[00041 A "stand" or set of rollers is required to produce each incremental
cross-sectional
profile as well as the ultimate cross-sectional profile of the product. Each
stand includes
cooperating contoured rollers which impart incremental bending upon the sheet
metal as
it passes through the stand, preferably without changing the thickness of the
material.
One will appreciate that roll forming machines are generally quite expensive
due to the
high cost of fabricating the closely tolerant sets of rollers of each stand
for each
incremental cross-sectional profile.
[0005] U.S. Patent No. 2,127,618 to Reimenschneider illustrates an exemplary
automobile side rail produced by roll forming. Japanese Patent Application No.
11-
188426 illustrates an exemplary channel member also produced by roll forming.
Exemplars of machines currently used for roll forming are described by U.S.
Patent No.
7,275,403 to Meyer and U.S. Patent No. 7,243,519 to Chuang.
[00061 Again, one will appreciate that such roll forming machines are
generally quite
expensive due to the high cost of fabricating sets of rollers for each stand.
Each set of
rollers generally require the use of hardened steels and other metals that are
highly
machined with close tolerances to a respective incremental cross-sectional
profile.
[00071 In light of the foregoing, it would be beneficial to have a forming
system which
overcomes the above and other disadvantages of known apparatuses for bending
sheet
materials.
BRIEF SUMMARY OF THE INVENTION
100081 One aspect of the present invention may be directed to a method for low-
force roll
folding of a two-dimensional sheet material having one or more predetermined
fold lines
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into a three-dimensional article. The method includes one or more of the steps
of
providing a sheet material with bend-facilitating structure extending along a
length of one
or more of the predetermined fold lines, providing a stand of folding rollers
configured to
effect bending of the sheet metal along the bend-facilitating structure, and
moving the
stand of folding rollers relative to the sheet material along the length of
one or more of
the predetermined fold lines to effect bending of the sheet material along the
bend-
facilitating structure.
[0009] The method may further include driving the sheet material through the
stand of
folding rollers. The method may further include driving the sheet material
through a
plurality of stands of folding rollers in order to effect a series of
incremental cross-
sectional profiles upon the sheet material. The method may further include
providing the
sheet material with bend-facilitating structure along a length of diverging
predetermined
fold lines. The method may further include providing the sheet material with
bend-
facilitating structure along a non-linear length of predetermined fold lines.
The folding
rollers may be substantially cylindrical and roll along the sheet material
adjacent to but
removed from the fold lines. The method may further include adjusting the
rotational
axes of the folding rollers relative to one another in order to accommodate
spring back
along the predetermined fold lines. The method may further include manually
rolling the
stand of folding rollers along the length of the predetermined fold lines.
[0010] Another aspect of the present invention is directed to a system for low-
force roll
folding of a two-dimensional sheet material having one or more predetermined
fold lines
into three-dimensional article. Preferably, the system includes a sheet
material with bend-
facilitating structure extending along a length one or more of the
predetermined fold
lines, a stand of rollers configured to effect bending of the sheet metal
along the bend-
facilitating structure, and a driver to move the stand of folding rollers
relative to the sheet
material along the length of one or more of the predetermined fold lines to
effect bending
of the sheet material along the bend-facilitating structure.
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[Doll] The system may further include a plurality of stands of folding
rollers, each stand
configured to effect and incremental cross-sectional profile upon the sheet
material. The
sheet material may include bend-facilitating structure along a link of
diverging
predetermined fold lines. The sheet material may include bend-facilitating
structure along
a nonlinear length predetermined fold lines. The folding rollers may be
substantially
cylindrical and roll line the sheet material adjacent to but removed from the
fold lines.
[00121 The methods and apparatuses of the present invention(s) have other
features and
advantages which will be apparent from or are set forth in more detail in the
accompanying drawings, which are incorporated herein, and the following
Detailed
Description of the Invention, which together serve to explain certain
principles of the
present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
100131 FIG. 1 a is an isometric view of an exemplary apparatus for low-force
roll folding
a three-dimensional article from a two-dimensional sheet material in
accordance with
various aspects of the present invention. FIG. lb is a schematic view of the
initial cross-
sectional profile of the two-dimensional sheet material. FIG. 1 c is a
schematic view of the
final cross-sectional profile of the three-dimensional article. FIG. 1 d is a
plan view of the
two-dimensional sheet material of FIG. lb.
100141 FIG. 2a is a plan view of another two-dimensional sheet material
prepared for
low-force roll folding in accordance with various aspects of the present
invention. FIG.
2b is a perspective view of a three-dimensional article formed with two-
dimensional
sheet materials similar to that shown in FIG. 2a.
[0015] FIG. 3a is a schematic view of other incremental cross-sectional
profiles as a two-
dimensional sheet material (top) is roll folded into a three-dimensional
article (bottom) in
accordance with various aspects of the present invention. FIG. 3b is a
schematic view of
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the incremental cross-sectional profiles of FIG. 3a passing through respective
sets of fold
rollers.
[00161 FIG. 4a is a schematic view of other incremental cross-sectional
profiles as a two-
dimensional sheet material (top) is roll folded into a three-dimensional
article (bottom) in
accordance with various aspects of the present invention. FIG. 4b is a
schematic view of
the incremental cross-sectional profiles of FIG. 4a passing through respective
sets of
rollers. FIG. 4c is a schematic view of the incremental cross-sectional
profiles of FIG. 4a
passing through another respective set of rollers similar to those shown in
FIG. 4b.
[00171 FIG. 5a is a schematic view of the incremental cross-sectional profiles
of FIG. 4a
passing through another respective set of rollers similar to those shown in
FIG. 4b. FIG.
5b is an enlarged cross-sectional view of a final set of rollers shown in FIG.
5a, said final
set of rollers configured to produce a cross-sectional profile, shown in FIG.
5c to
accommodate spring-back resulting in the final cross-sectional profile of FIG.
5d. FIG. 5e
is an enlarged detail of the rollers of FIG. 5b. FIG. 5f is a schematic side
view of the
rollers of FIG. 5b illustrating adjustment of the upper roller in phantom.
100181 FIG. 6a is a schematic view of incremental cross-sectional profiles of
another
two-dimensional sheet material (top) passing through respective sets of
rollers to form a
three-dimensional article (bottom) in accordance with various aspects of the
present
invention. FIG. 6b is an enlarged set of folding rollers shown in FIG. 6a.
[0019] FIG. 7a is an isometric view of another exemplary apparatus for low-
force roll
folding a three-dimensional article from a two-dimensional sheet material in
accordance
with various aspects of the present invention. FIG. 7b is an enlarged detail
of the
apparatus of FIG. 7a
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[0020] FIG. 8 is a plan view of another two-dimensional sheet material similar
to that
shown in FIG. 7a, but prepared for low-force roll folding along non-parallel
and
diverging fold lines in accordance with various aspects of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
100211 Reference will now be made in detail to various embodiments of the
present
invention(s), examples of which are illustrated in the accompanying drawings
and
described below. While the invention(s) will be described in conjunction with
exemplary
embodiments, it will be understood that present description is not intended to
limit the
invention(s) to those exemplary embodiments. On the contrary, the invention(s)
is/are
intended to cover not only the exemplary embodiments, but also various
alternatives,
modifications, equivalents and other embodiments, which may be included within
the
spirit and scope of the invention as defined by the appended claims.
[00221 Turning now to the drawings, wherein like components are designated by
like
reference numerals throughout the various figures, attention is directed to
FIG. 1 a, which
illustrates an exemplary roll folding system generally designated by the
numeral 30 that
may be used to fold a two-dimensional sheet material 32 (see FIG. lb and FIG.
I d) into
three-dimensional article 33 (see FIG. 1 c). The roll folding system is
designed to be used
with ductile sheet materials having engineered fold lines 35 which facilitate
bending
along predetermined fold lines. As the sheet material is guided through the
machine along
a predetermined path of travel, its cross-sectional profile is gradually
transformed from a
flat sheet into a three-dimensional article having a desired cross-sectional
profile.
100231 In contrast to conventional roll forming machines, which require a
carefully
crafted set of rollers for each stand conforming with an incremental cross-
sectional
profile, the roll folding system of the present invention may utilize simple
roller wheels,
which need not conform with any particular cross-sectional profiles.
Accordingly, the roll
folding system of the present invention greatly reduces the capital costs of
roll folding
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equipment because it does not require costly machining of rollers precisely
conforming to
cross-sectional profiles.
[00241 The roll folding systems in accordance with the present invention are
particularly
suited for bending two-dimensional sheet materials having engineered fold
lines which
utilize various fold geometries and configurations including, but not limited
to, those
disclosed by U.S. Patent Nos. 6,481,259, U.S. Patent No. 6,877,349 , U.S.
Patent
Application Publication No. US 2006/0021413 Al, U.S. Patent No. 7,152,449,
U.S.
Patent No. 7,032,426, U.S. Patent No. 7,152,450, U.S. Patent Application
Publication No.
US 2005/0005670 Al, U.S. Patent No. 7,263,869, U.S. Patent No. 7,222,511, U.S.
Patent
Application Publication No. US 2005/0257589 Al, U.S. Patent Application
Publication
No. US 2006/0213245 Al, U.S. Patent No. 7,296,455, U.S. Patent Application
Publication No. US 2006/0130551 Al, U.S. Provisional Patent Application No.
60/911,910, U.S. Provisional Patent Application No. 60/974,466, U.S.
Provisional Patent
Application No. 60/974,468, and U.S. Patent Application No. 11/925,195, the
entire
contents of which patents and patent applications are incorporated herein by
this
reference.
[00251 The roll folding systems of the present invention is designed to take
advantage of
various aspects of manufacturing with engineered fold lines. For example,
accurate
machine tool tolerances are relatively less critical because the location of
desired fold
lines are engineered into the sheets of material. Accordingly, the roll
folding systems of
the present invention can, but need not, take the form of a high-efficiency
light-duty
machine which may be capable hundreds of thousands and/or millions of cycles
due to
relatively minimal wear and tear. Special materials, expensive and time-
consuming
machining, hardening, heat treatments, and/or other costly processes may be
reduced or
avoided because the need for precise machine tool tolerances is reduced.
Instead, the
tolerances are built into the sheet of material whereby a less expensive and
lighter-duty
roll folding may be utilized to fold a two-dimensional sheet of material into
its final
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shape, or in some cases one or more intermediate shapes. As such, the present
roll folding
systems may be constructed with milder steel, laser cut parts and other
relatively
inexpensive components such as those including mild steels, plastics,
composites and/or
other materials typically considered to be too soft to be built for metal
forming
equipment, as well as die cast and other relatively less precise componentry.
Of course,
the foregoing does not necessarily preclude heavy-duty construction using
hardened
steels. Rather, it allows enhanced flexibility depending on factors such as
duty cycle,
economy, weight, and the like.
[00261 One will appreciate, however, that the present roll folding systems are
also suited
for bending other types of ductile sheet materials about a fold line
including, but not
limited to, sheet metal prepared with the above-mentioned engineered fold
lines,
predetermined fold lines defined by scoring and/or other suitable means.
[00271 One will appreciate that a number three-dimensional products may be
formed by
the roll folding of the present invention which include both relatively narrow
flanges and
relatively wide flanges. For example, the three-dimensional products may
include, but are
not limited to, various enclosure components, electronic chassis components,
automotive
components, appliance components, transport components, construction
components,
HVAC components, aerospace components, and the like.
100281 Returning to FIG. la, an exemplary roll folding system 30 generally
includes a
machine chassis 37 configured to support and position various sub-assemblies
of the roll
folding system. For example, upper receiving drive rollers 39 are rotatably
supported by
the machine chassis in an otherwise conventional manner and driven by a
suitable drive
means. Upper exiting drive rollers 40 are similarly mounted and driven on the
machine
chassis. Lower receiving and exiting drive rollers 39', 40' are also provided
in a similar
fashion. The drive rollers are configured to receive and propel sheet material
32 through
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the roll folding system as the roll folding system folds the sheet material
into three-
dimensional article 33.
[00291 One or more guide rollers 42 may be provided to generally support and
guide the
sheet material as it passes through the roll folding system.
[0030] A number of "stands" 44 or sets of folding rollers 46 are also provided
to impart
the folding force upon the sheet material. The folding rollers may be spring
loaded to
apply a relatively uniform force against the sheet material as the sheet
material passes by
the folding rollers. The folding rollers are configured and positioned to roll
along
continuous surfaces 47 of the sheet material substantially parallel to or
along respective
fold lines in order to impart folding force upon the sheet material as the
sheet material
passes through the respective set of folding rollers.
100311 As noted above, sheet material 32 includes preformed engineered fold
lines and
thus requires less force to effect bending along the fold lines. Furthermore,
as the
preformed engineered fold lines self identify precisely where the sheet
material will bend
and in particular where a deformation will occur, the folding rollers need
only
approximately position the continuous surfaces to effect bending.
[00321 Furthermore, since the sheet material includes engineered fold lines
35, the
amount of force necessary to effect bending of the sheet material is greatly
reduced. In
contrast to conventional roll forming machines, which require a carefully
crafted set of
hardened and/or relatively hard rollers for each stand of rollers conforming
with an
incremental cross-sectional profile, the roll folding system of the present
invention may
utilize simple off-the-shelf roller wheels, which need not conform with any
particular
cross-sectional profiles. For example, the roller wheels may be formed of
urethane,
rubber, or other suitable materials that are applicable to relatively low
force
environments. For example, Delrin skids may provide an alternative to the
rollers for
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applying force against the sheet material as it passes by each stand.
Accordingly, the roll
folding system of the present invention greatly reduces the capital costs
associated with
conventional roll forming equipment because it does not require the machining
of rollers
precisely conforming to cross-sectional profiles.
[00331 One will appreciate that the light-duty nature of the present roll
folding system
may facilitate roll folding of pre-painted sheet materials wherein the rollers
and/or skids
would effect little scuffing and/or scrubbing along the surface of the sheet
material as it
passes through the stands. Also, one will appreciate that relatively large-
radii roller
wheels may be utilized, and may facilitate loading of, or receiving of the
sheet material
into and through each stand.
[00341 In the illustrated embodiment, roll folding system 30 includes an upper
series 49
and a lower series 51 of stands 44, in which the two-dimensional sheet
material 32 is fed
to left-to-right into roll folding system 30 and through the upper series of
stands to form
an intermediate article 53, which intermediate article may again be fed right-
to-left into
the roll folding system through the lower series of stands to form the final
three-
dimensional article 33. The roll folding system is preferably configured to
guide the
intermediate article from the upper series to the lower series of stands by
conventional
means, for example, allowing the intermediate article to drop or otherwise
move down in
the direction of arrow D. The "out-and-return" configuration of the roll
folding system is
particularly advantageous in that a single operator may operate the roll
folding system
from a single position (e.g., position P). One will appreciate, however, that
a single series
of stands may be provided in which the sheet material moves outwardly in a
single
direction.
[00351 In the illustrated embodiment, the upper series is provided with four
stands 44,
that is four sets of rollers corresponding with four incremental cross-
sectional profiles,
and the lower series is provided with three stands 44' or three sets of
rollers
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corresponding with two additional incremental cross-sectional profiles and the
final
cross-sectional profile of three-dimensional article 33. One will appreciate,
however, that
one, two, three or more stands may be provided to effect the desired amount of
bending.
[00361 In contrast to conventional roll forming technology, the roll folding
system of the
present invention may also be used to form three-dimensional articles having
nonuniform
cross-sectional profiles. For example, FIG. 2a illustrates a sheet of material
having fold
lines 35a that are not parallel but instead converge toward one another. Such
a
configuration of fold lines may be used to produce articles of varying cross-
sectional
width dimensions such as the horn-shaped article 54 shown in FIG. 2b. As is
shown in
FIG. 2a, the fold lines on either side may be parallel to one another (see,
e.g., fold lines
35a) or may converge toward one another (see, e.g., fold lines 35a').
[00371 As shown in FIG. 1 a, roll folding system 30 may be provided with one
or more
tuning knobs 56 to adjust the of each stand 44 by suitable means. One will
also appreciate
that a tuning knob may be provided for each subset of stand rollers in order
to
independently adjust the subset of rollers on each lateral side of the stand.
100381 The roll folding system of the present invention is particularly useful
for folding
sheet materials into a wide variety of three-dimensional articles. For
example, with
reference to FIG. 3a and FIG. 3b, roll folding system 30 may be used to fold
sheet
material 32b in to a three-dimensional article 33b in the form of a channel-
shaped closed
box beam. In the illustrated embodiment, eight stands 44b of rollers are
utilized to flare
each side of sheet material 32b upwardly and inwardly to form a closed box
beam 58, as
shown in FIG. 3b. The uppermost stand gently flares the outermost edge of
sheet material
32b upwardly, while the next two stands continue to flare the outermost edge
upwardly
and began to flare inwardly while flaring inner sidewalls upwardly. The next
stand begins
to guide the outermost edge inwardly, while the remaining stands further guide
the
outermost edge and sidewalls to close the box beam. As can be seen in this
schematic
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series, the rollers of each stand may be uniformly sized wheels which are
configured to
roll upon the flat surfaces of sheet material 32b between fold lines 35b.
[00391 One will appreciate that the orientation of folding rollers may very
widely
depending upon the desired cross-sectional profile. For example and with
reference to
FIG. 4a, the roll folding system of the present invention may be utilized to
create a
double channel beam 60. One will further appreciate, that a number of
configurations
may be utilized to affect folding of a particular desired cross-sectional
profile, as can be
seen in FIG. 4b and FIG. 4c. For example, each stand 44c of folding rollers
46c may be
rotatably mounted on parallel axes, as shown in FIG. 4b. Alternatively, each
stand 44d
may include folding rollers 46d rotatably mounted on orthogonal axes. One will
appreciate that limiting rotational axes to either horizontal or
perpendicular/vertical axes
simplifies machine design. Also, by positioning the wheels substantially
perpendicular to
the surface of the sheet material, one may limit the amount of scrubbing or
scuffing of the
folding rollers upon the sheet material.
[00401 In still a further embodiment of the present invention, contoured
folding rollers 61
may be utilized to impart folding forces upon the sheet material, as shown in
FIG. 5a, in
which a two-dimensional sheet material is also roll folded into a three-
dimensional article
33e (bottom). With reference to FIG. 5b and FIG. 5e, the contoured folding
rollers may
be configured with a cooperating recess 63 and protrusion 65 in order to over
bend sheet
material 32e (see FIG. 5c) in order to accommodate spring-back resulting in a
desired
cross-sectional profile (see FIG. 5d). One will appreciate that other
configurations may be
utilized to effect over-bending including the positioning of folding rollers.
In this
embodiment, the contoured folding rollers are rotatably mounted on parallel
axes and, as
such, may be easily adjusted relative to one another. For example and as shown
in FIG.
5f, one of the contoured rollers may be adjusted "within plane" such that the
axis of one
roller 61 may be slid back-and-forth relative to the axis of a cooperating
roller 61' in
order to adjust the distance between recess 63 and protrusion 65. In the
illustrated
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embodiment, roller 61.5 may be slid back and forth within a horizontal plane
to adjust the
amount of over-bending, that is, the amount of bending beyond a desired angle
in order to
accommodate spring back. One will appreciate that the rollers may be
configured such
that they are adjustable by sliding or otherwise adjusted along an inclined
plane or along
a vertical plane instead of a horizontal direction.
100411 FIG. 6a is a schematic view of a series of incremental cross-sectional
profiles of
yet another two-dimensional sheet material passing through respective sets of
rollers to
form a three-dimensional article 33f (bottom) in accordance with various
aspects of the
present invention. In this embodiment, folding rollers 46f are fixed relative
to one another
in a roller mount 67 but positioned in such a manner that the rollers follow
along fold
lines 35f, 35f , 35f '. With such configuration, the folding rollers impart
folding forces
upon sheet material 32f along the fold lines and, as such, the configuration
tends to
follow the fold lines in the sheet material due to the geometric constraints
created by the
position of the fold lines. In one embodiment, the roller mount may be in the
form of a
hand tool having a grip 68 in which case, an operator may manually sweep a
first roller
mount along the length of the sheet material to impart the first incremental
cross-
sectional profile thereon, and follow by sweeping other roller mounts to
impart the
subsequent incremental cross-sectional profiles thereon, and ultimately, the
final cross-
sectional profile thereon.
[00421 In another exemplary embodiment of the present invention, roll folding
system
30g is similar to roll folding system 30g described above but it incorporates
movable
roller mounts in order to fold a two-dimensional sheet material 32g into a
three-
dimensional article 33g having compound curves as shown in FIG. 7. Like
reference
numerals have been used to describe like components of roll folding system 30
and roll
folding system 30g.
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[00431 In this embodiment, each stand 44g includes opposing roller mounts 67g
slidably
supported by a machine chassis 37g such that folding rollers 46g are allowed
to move
laterally in order to effect bending and follow the lateral profiles of sheet
material 32g
Each roller mount is allowed to move up and down in order to follow the basic
curvature
of the sheet material as the sheet material is bent along fold lines 35g, as
shown in FIG.
7a. Accordingly, the roller mounts 67g and the respective stand folding
rollers 46g are
limited to two degrees of freedom. The folding rollers float in the sense that
they may
move up-and-down and in-and-out, but they are fixed relative to the
longitudinal length
of machine chassis 37g. As such, respective sets of folding rollers may be
provided to
effect each incremental cross-sectional profile as the two-dimensional sheet
of material
32g passes through roll folding system 30g. As the orientation of rollers
mounted on each
roller mount is fixed relative to one another, and because an upper roller and
at a lower
roller is aligned with respective inside corners or valleys of the incremental
cross-
sectional profiles, the set of rollers will closely follow along the path of
the fold lines.
One will appreciate that the rollers may be configured such that their
orientation may
vary in order to accommodate fold lines that converge or diverge from one
another such
as those shown in FIG. 8. Preferably springs or other suitable biasing means
are utilized
to bias the roller mounts back to an initial position to facilitate receipt of
the sheet
material between the respective folding rollers.
[00441 One will appreciate that the roll folding system of the present
invention may be
utilized in combination with other conventional metalworking stations or
processes. For
example, the present roll folding systems may be utilized with various
configurations that
punch and cut off parts during otherwise conventional continuous operations,
such as
cutting a part to length when supplying coils are used to supply the sheet
metal "blanks"
to the roll folding system. Further, various configurations of stations may be
utilized to
add features such as holes, notches, embossments, and/or shear forms by
punching,
stamping, and or other known processes found in conventional roll forming
lines. For
example, fastening structures 70 (see, e.g., FIG. 2a and FIG. 2b) may take the
form of
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spring clips of the type disclosed by U.S. Patent Application Publication No.
US
2006/0277965 Al, and/or other integral fastening structure, which structure
may be
stamped directly into the sheet metal either before or after the sheet metal
passes through
the roll folding system.
[00451 For convenience in explanation and accurate definition in the appended
claims,
the terms "up" or "upper", "down" or "lower", "inside" and "outside" are used
to
describe features of the exemplary embodiments with reference to the positions
of such
features as displayed in the figures.
[00461 In many respects various modified features of the various figures
resemble those
of preceding features and the same reference numerals followed by subscripts
"a", "b",
"c", "d", "e", 'f' and "g" designate corresponding parts.
[00471 The foregoing descriptions of specific exemplary embodiments of the
present
invention have been presented for purposes of illustration and description.
They are not
intended to be exhaustive or to limit the invention to the precise forms
disclosed, and
obviously many modifications and variations are possible in light of the above
teachings.
The exemplary embodiments were chosen and described in order to explain
certain
principles of the invention and their practical application, to thereby enable
others skilled
in the art to make and utilize various exemplary embodiments of the present
invention, as
well as various alternatives and modifications thereof. It is intended that
the scope of the
invention be defined by the Claims appended hereto and their equivalents.
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