U.S. patent application number 12/235571 was filed with the patent office on 2009-04-23 for sheet of material with fluid-resistant bend controlling displacements and method of forming the same.
This patent application is currently assigned to Industrial Origami, Inc.. Invention is credited to Max W. DURNEY, Ryan LAM, Radha VAIDYANATHAN.
Application Number | 20090100894 12/235571 |
Document ID | / |
Family ID | 40468818 |
Filed Date | 2009-04-23 |
United States Patent
Application |
20090100894 |
Kind Code |
A1 |
DURNEY; Max W. ; et
al. |
April 23, 2009 |
Sheet of Material with Fluid-Resistant Bend Controlling
Displacements and Method of Forming the Same
Abstract
A method of preparing a two-dimensional sheet of material for
bending along a bend line to form a three-dimensional article
having a fluid-resistant bend includes the steps of forming at
least one bend-controlling displacement in the thickness direction
of the sheet of material, a portion of a periphery of the
bend-controlling displacement proximate the bend line defining a
sheared face directed toward an opposed sheet surface in the sheet
of material on an opposite side of the bend line, and bending the
sheet of material. A balancing of the forces during bending
produces face-to-surface engagement between the sheared face and
the opposed sheet surface such that the sheet material is
substantially fluid-resistant along the bend line.
Inventors: |
DURNEY; Max W.; (San
Francisco, CA) ; VAIDYANATHAN; Radha; (Los Altos,
CA) ; LAM; Ryan; (San Mateo, CA) |
Correspondence
Address: |
MORGAN, LEWIS & BOCKIUS, LLP
ONE MARKET SPEAR STREET TOWER
SAN FRANCISCO
CA
94105
US
|
Assignee: |
Industrial Origami, Inc.
San Francisco
CA
|
Family ID: |
40468818 |
Appl. No.: |
12/235571 |
Filed: |
September 22, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60974466 |
Sep 22, 2007 |
|
|
|
Current U.S.
Class: |
72/379.2 |
Current CPC
Class: |
B21D 5/00 20130101; B21D
11/10 20130101 |
Class at
Publication: |
72/379.2 |
International
Class: |
B21D 31/00 20060101
B21D031/00 |
Claims
1. A method of preparing a two-dimensional sheet of material for
bending along a bend line to form a three-dimensional article
having a fluid-resistant bend, the method comprising: forming at
least one bend-controlling displacement in the thickness direction
of the sheet of material, a portion of a periphery of the
bend-controlling displacement proximate the bend line defining a
sheared face directed toward an opposed sheet surface in the sheet
of material on an opposite side of the bend line; and bending the
sheet of material whereby a balancing of the forces during bending
produces face-to-surface engagement between the sheared face and
the opposed sheet surface such that the sheet material is
substantially fluid-resistant along the bend line.
2. A method according to claim 1, wherein the forming step includes
forming a plurality of bend-controlling displacements having a pair
of bending straps in the sheet of material intersecting the bend
line and a respective sheared face extending therebetween, and
wherein the bending step subjects the straps to tension such that
the sheared face closely abuts against the opposed sheet surface
when the sheet of material is bent.
3. A method according to claim 2, wherein the plurality of
bend-controlling displacements are formed in the sheet of material
with a sheared edge extending along a respective sheared face along
one side of the bend line, and wherein the forming step defines an
opposed face opposite each sheared face such that bending produces
edge-to-face engagement of the sheet of material during the bending
step.
4. A method according to claim 1, wherein the bending step seals
the opposed surface to the sheared face when the sheet of material
is bent.
5. A method according to claim 4, wherein the seal is substantially
formed by close abutment of the sheared face to the opposed
surface.
6. A method according to claim 5, wherein abutment is substantially
uniform along the sheared face.
7. A method according to claim 5, wherein the seal is formed with
substantially no use of sealing materials.
8. A method according to claim 4, further including after the
forming step, adhering a layer of coating material to the sheet of
material across the bend-controlling displacements.
9. A method according to claim 8, wherein the adhering step
provides a continuous layer of flexible coating material to the
sheet of material across the plurality of bend-controlling
displacements, which continuous layer remains substantially intact
after the bending step.
10. A method according to claim 9, wherein the coating material is
paint.
11. A method according to claim 4, further including after the
bending step, adhering a layer of coating material to the sheet of
material across the bend-controlling displacements.
12. A method according to claim 1, wherein the forming step forms
the bend-controlling displacement with a substantially oval-shape
and includes a periphery with end portions and a crown portion
extending between the end portions.
13. A method according to claim 12, wherein the forming step
provides the crown portion of the bend-controlling displacement
with an arcuate profile.
14. A method according to claim 12, wherein the crown portion is a
large radii arc.
15. A method according to claim 12, wherein the end portions are a
small radii arc.
16. A method according to claim 12, the bend-controlling
displacement further including transition zones between the crown
portion and the end portions.
17. A method according to claim 16, wherein the transition zones
have a radius of curvature intermediate the radii of curvature of
the end portions and the crown portion.
18. A method according to claim 16, wherein the first order
derivative of the radius of curvature of the sheared face along the
crown portion, the transition zones and the end portions is
substantially uniform.
19. A method according to claim 1, wherein the forming step forms a
joggle zone connecting an unsheared portion of the bend-controlling
displacement to the sheet material, wherein each end portion
includes a portion of the sheared face and a portion of the joggle
zone.
20. A method according to claim 1, wherein the sheared edge extends
below the opposed sheet surface a distance that is at least 75% the
thickness of the material.
21. A method according to claim 1, wherein the sheared edge has a
z-depth of between 0.095-0.110 mm.
22. A method according to claim 1, wherein the sheet of material is
steel.
23. A method according to claim 1, wherein the sheared face extends
to within approximately 40.degree. of a longitudinal axis of the
displacement with respect to a radial center of the end
portion.
24. A method according to claim 1, wherein the forming is
accomplished using one of a stamping process, punching process, a
roll forming process, or an embossing process.
25. A method according to claim 1, wherein the three-dimensional
article is a NEMA-3 pull box.
26. A method according to claim 13, wherein the curved crown
portion is dimensioned to produce the face-to-surface engagement
between the sheared face and the opposed sheet surface.
27. A method according to claim 26, wherein the end portions have a
smaller radius of curvature than the crown portions.
28.-35. (canceled)
36. A two-dimensional sheet of material formed for bending along a
bend line to form a three-dimensional article having a
fluid-resistant bend, the sheet of material comprising: a sheet of
material including a bend-controlling displacement in the thickness
direction of the sheet of material, a portion of a periphery of the
bend-controlling displacement proximate the bend line defining a
sheared face directed toward an opposed sheet surface in the sheet
of material on an opposite side of the bend line, the sheared face
and opposed sheet surface configured and positioned to produce
face-to-surface engagement of the sheet of material after bending
such the bend is substantially fluid-resistant when bent.
37.-50. (canceled)
51. A rigid three-dimensional article formed by the method
according to claim 1.
52. A rigid three-dimensional article including a sheet of material
according to claim 36.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent
Application No. 60/974,466 filed Sep. 22, 2007, entitled Sheet Of
Material With Fluid-Resistant Bend Controlling Displacements And
Method Of Forming The Same, the entire contents of which is
incorporated herein for all purposes by this reference.
FIELD OF THE INVENTION
[0002] This invention relates, in general, to preparing a sheet of
material for bending along a bend line into a three-dimensional
structure, and more particularly to preparing a sheet of material
with bend controlling displacements for folding into a
three-dimensional structure with fluid-resistant bends.
BACKGROUND OF THE INVENTION
[0003] The present invention is related to techniques for preparing
a sheet of material to bend or fold along a desired bend line. Such
techniques are disclosed in depth in U.S. Pat. Nos. 7,152,449,
7,032,426, 6,877,349, 6,481,259, and 7,263,869, all to Durney et
al., which are each incorporated herein for all purposes by
reference in their entireties. In these applications several
techniques and manufacturing processes for forming slits and/or
grooves that will precisely control bending of sheet material are
disclosed. The emphasis in these related applications is in
connection with the use of slits which penetrate completely through
the sheet of material. Both slits and grooves can be provided which
control bending.
[0004] These innovative slitting and displacement techniques allow
preparation of a sheet of material in two dimensions for folding
along a precisely-located bend line. However, these techniques and
other conventional techniques may create a gap in the sheet of
material and along the resulting bend line, the edge of the
bend-controlling structures may not provide a sealed bend. For
example, slits and displacements with large kerfs, punch heights,
and/or planar displacements are more prone to create "light" or
gaps in the bend line after bending.
[0005] For example, U.S. Pat. No. 6,640,605 to Gitlin et al.
discloses slits or grooves along the bend line or offset on
opposite sides of the bend line. In the Gitlin et al. patent, the
bending webs between discontinuous grooves have centerlines which
are parallel to the desired bend line. This approach requires that
the bending straps between slits undergo substantial twisting and
little bending while the continuous webs at the bottom of the slits
are being bent. The approach results in little, if any, fluid
resistance, which may be entirely insufficient for many
applications such as HVAC, ducts, and weather-resistant
enclosures.
[0006] In light of the foregoing, it would be beneficial to have
methods and apparatuses which overcome the above and other
disadvantages of known methods. What is needed is a method which is
capable of preparing sheet materials that are capable of being
folded into three-dimensional products having bends that are
fluid-resistant.
BRIEF SUMMARY OF THE INVENTION
[0007] In summary, one aspect of the present invention is directed
to a method of preparing a two-dimensional sheet of material for
bending along a bend line to form a three-dimensional article
having a fluid-resistant bend. The method may include one or more
of the following steps: forming at least one bend-controlling
displacement in the thickness direction of the sheet of material, a
portion of a periphery of the bend-controlling displacement
proximate the bend line defining a sheared face directed toward an
opposed sheet surface in the sheet of material on an opposite side
of the bend line; and bending the sheet of material whereby a
balancing of the forces during bending produces face-to-surface
engagement between the sheared face and the opposed sheet surface
such that the sheet material is substantially fluid-resistant along
the bend line.
[0008] The forming step may include forming a plurality of
bend-controlling displacements having a pair of bending straps in
the sheet of material intersecting the bend line and a respective
sheared face extending therebetween, and wherein the bending step
subjects the straps to tension such that the sheared face closely
abuts against the opposed sheet surface when the sheet of material
is bent. The plurality of bend-controlling displacements may be
formed in the sheet of material with a sheared edge extending along
a respective sheared face along one side of the bend line, and
wherein the forming step defines an opposed face opposite each
sheared face such that bending produces edge-to-face engagement of
the sheet of material during the bending step. The bending step may
seal the opposed surface to the sheared face when the sheet of
material is bent. The seal may be substantially formed by close
abutment of the sheared face to the opposed surface. Abutment may
be substantially uniform along the sheared face. The seal may be
formed with substantially no use of sealing materials. The method
may further include after the forming step, adhering a layer of
coating material to the sheet of material across the
bend-controlling displacements. The adhering step provides a
continuous layer of flexible coating material to the sheet of
material across the plurality of bend-controlling displacements,
which continuous layer remains substantially intact after the
bending step. The coating material may be paint. The method may
further include after the bending step, adhering a layer of coating
material to the sheet of material across the bend-controlling
displacements.
[0009] The forming step forms the bend-controlling displacement
with a substantially oval-shape and may include a periphery with
end portions and a crown portion extending between the end
portions. The forming step provides the crown portion of the
bend-controlling displacement with an arcuate profile. The crown
portion may be a large radii arc. The end portions may be a small
radii arc. The bend-controlling displacement may further include
transition zones between the crown portion and the end portions.
The transition zones have a radius of curvature intermediate the
radii of curvature of the end portions and the crown portion.
[0010] The forming step forms a joggle zone connecting an unsheared
portion of the bend-controlling displacement to the sheet material,
wherein each end portion may include a portion of the sheared face
and a portion of the joggle zone. The sheared edge extends below
the opposed sheet surface a distance that may be at least 75% the
thickness of the material. The sheared edge has a z-depth of
between 0.095-0.110 mm. The sheet of material may be steel. The
sheared face may extend to within approximately 40.degree. of a
longitudinal axis of the displacement with respect to a radial
center of the end portion. The forming may be accomplished using
one of a stamping process, punching process, a roll forming
process, or an embossing process. The three-dimensional article may
be a NEMA-3 pull box.
[0011] Another aspect of the present invention is directed to a
method of preparing a two-dimensional sheet of material for bending
along a bend line to form a three-dimensional article having a
fluid-resistant bend. The method may include: forming at least one
bend-controlling displacement in the thickness direction of the
sheet of material with a substantially oval shape, the
bend-controlling displacement including a periphery with end
portions and a curved crown extending between the end portions
proximate the bend line, the bend-controlling displacement
including a sheared face extending along the crown portion and into
the end portions and facing an opposed sheet surface in the sheet
of material on an opposite side of the bend line; bending the sheet
of material about the bend line. The curved crown portion may be
dimensioned to produce face-to-surface engagement between the
sheared face and the opposed sheet surface.
[0012] The end portions may have a smaller radius of curvature than
the crown portions. The crown portion may be a large radii arc. The
end portions may be a small radii arc. The bend-controlling
displacement may further include transition zones between the crown
portion and the end portions. The transition zones have a radius of
curvature intermediate the radii of curvature of the end portions
and the crown portion. The bend line may be substantially
fluid-resistant when the sheet of material is bent. A portion of
the periphery proximate the bend line may define a sheared face
directed toward an opposed sheet surface in the sheet of material
on an opposite side of the bend line, whereby during the bending
step a balancing of forces during bending produces face-to-surface
engagement between the sheared face and the opposed sheet surface
such that the sheet material is substantially fluid-resistant along
the bend line. The forming step may form a joggle zone connecting
an unsheared portion of the bend-controlling displacement to the
sheet material, wherein each end portion may include a portion of
the sheared face and a portion of the joggle zone. The sheared face
may extend to within approximately 40.degree. of a longitudinal
axis of the displacement with respect to a radial center of the end
portion.
[0013] A further aspect of the present invention is directed to a
two-dimensional sheet of material formed for bending along a bend
line to form a three-dimensional article having a fluid-resistant
bend. The sheet of material may include a sheet of material
including a bend-controlling displacement in the thickness
direction of the sheet of material, a portion of a periphery of the
bend-controlling displacement proximate the bend line defining a
sheared face directed toward an opposed sheet surface in the sheet
of material on an opposite side of the bend line, the sheared face
and opposed sheet surface configured and positioned to produce
face-to-surface engagement of the sheet of material after bending
such the bend is substantially fluid-resistant when bent.
[0014] The bend-controlling displacement having an oval shape and
may further include a periphery with end portions and a crown
portion extending between the end portions. The crown portion may
have an arcuate profile. The end portions have an arcuate profile
with a radius of curvature smaller than a radius of curvature of
the crown portion. The bend-controlling displacement may further
include transition zones between the crown portion and the end
portions. Each of the transition zones may have a radius of
curvature intermediate the radii of curvature of the end portions
and the crown portion. The bend-controlling displacements may
further include a joggle zone connecting an unsheared portion of
the bend-controlling displacement to the sheet material, wherein
each end portion may include a portion of the sheared face and a
portion of the joggle zone.
[0015] Yet a further aspect is directed to a two-dimensional sheet
of material formed for bending along a bend line to form a
three-dimensional article including a sheet of material including a
bend-controlling displacement in the thickness direction of the
sheet of material with a substantially oval shape, the
bend-controlling displacement including a periphery with end
portions and a curved crown extending between the end portions
proximate the bend line, the bend-controlling displacement
including a sheared face extending along the crown portion and into
the end portions and facing an opposed sheet surface in the sheet
of material on an opposite side of the bend line. The curved crown
portion may be dimensioned to produce face-to-surface engagement
between the sheared face and the opposed sheet surface.
[0016] The end portions may have a smaller radius of curvature than
the crown portions. The crown portion may be a large radii arc. The
end portions may be a small radii arc. The bend-controlling
displacement may further include transition zones between the crown
portion and the end portions. The transition zones have a radius of
curvature intermediate the radii of curvature of the end portions
and the crown portion.
[0017] Still a further aspect of the present invention is directed
to a rigid three-dimensional article formed by bending a
two-dimensional sheet of material along at least one bend line. The
article may include at least one bend-inducing displacement in the
thickness direction of the sheet of material, a portion of a
periphery of the bend-inducing displacement proximate the bend line
defining a sheared face directed toward an opposed sheet surface in
the sheet of material on an opposite side of the bend line. The
sheared face and opposed sheet surface may be in engagement such
that the sheet material is substantially fluid-resistant along the
bend line. The sheared face and opposed sheet surface may be in
close abutment along a periphery of the sheared face.
[0018] The methods, sheet materials, and structures of the present
inventions have other features and advantages which will be
apparent from or are set forth in more detail in the accompanying
drawings, which are incorporated in and form a part of this
specification, and the following Detailed Description of the
Invention, which together serve to explain the principles of the
present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a perspective view of a three-dimensional
enclosure prepared in accordance with the present invention having
a fluid-resistant bend line.
[0020] FIG. 2 is a top view of the prepared two-dimensional sheet
of material of FIG. 1 prior to folding into the three-dimensional
article.
[0021] FIG. 3 is a schematic plan view of the two-dimensional sheet
of material of FIG. 2 having bend-controlling displacements on
alternate sides of the end line, and FIG. 3A is an enlarged detail
thereof.
[0022] FIG. 4A is an enlarged perspective view of a plurality of
bend-controlling displacements along a multiple bend line utilized
in the sheet of material of FIG. 2 illustrating displacements
extending downward, and FIG. 4B is an isometric rendering of a
portion of the same.
[0023] FIG. 5A is an enlarged perspective view of the plurality of
bend-controlling displacements after the sheet of material of FIG.
2 has been folded into the three-dimensional article of FIG. 1 and
FIG. 5B is an isometric rendering of a portion of the same.
[0024] FIG. 6A is an enlarged isometric rending view of a portion
of a sheet material with bend-controlling displacements of FIG. 3,
and FIG. 6B is an enlarged isometric rendering of the portion after
the sheet material has been bent along the bend line.
[0025] FIG. 7 is a schematic view of a bend-controlling
displacement utilized in the sheet of material of FIG. 2
illustrating a periphery of the bend-controlling displacement.
[0026] FIG. 8 is a schematic view of a bend-controlling
displacement utilized in the sheet of material of FIG. 2
illustrating the transition from a sheared face to a transition
zone along the periphery of the bend-controlling displacement.
[0027] FIG. 9 is a schematic view of exemplary tooling profiles and
orientation thereof used to form the bend-controlling displacement
of FIG. 2.
[0028] FIGS. 10 and 11 are schematic views of other tooling
profiles used to form the bend-controlling displacements of FIGS. 2
and 3.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Reference will now be made in detail to the preferred
embodiments of the invention, examples of which are illustrated in
the accompanying drawings. While the invention will be described in
conjunction with the preferred embodiments, it will be understood
that they are not intended to limit the invention to those
embodiments. On the contrary, the invention is intended to cover
alternatives, modifications and equivalents, which may be included
within the spirit and scope of the invention as defined by the
appended claims.
[0030] Bend-controlling structures control and precisely locate the
bending of a two-dimensional sheet material into three-dimensional
structures. Such bend-controlling structures lower the cost and
complexity of manufacturing processes and allow for greater
flexibility of manufacture and time savings. Bend-controlling
structures such as displacements and the like allow a sheet of
material to be prepared simply in the flat and later folded into
complicated three-dimensional structures.
[0031] Such structures often include applications where it is
desirable to create a fluid-resistant bend line in the region of
the bend-controlling structures. However, processes for forming the
bend-controlling structures such as punching, stamping, machining,
photo-etching, embossing, and the like usually create gaps or
separations in the sheet of material. The present application,
therefore, illustrates how bend-controlling structures,
particularly, bend-controlling displacements can be formed in a
sheet of material that can be bent into a fluid-resistant
three-dimensional structure.
[0032] Preferably, the sheet of material is a non-compressible
material. Suitable materials for the sheet of material include, but
are not limited to, metals such as steel, mild steel, stainless
steel, galvanized steel, aluminum, alloys, and plastics.
[0033] Turning now to the drawings, wherein like components are
designated by like reference numerals throughout the various
figures, FIGS. 1-5 illustrate a three-dimensional article 30 having
a plurality of bend lines 32. The exemplary three-dimensional
article is formed from a two-dimensional sheet of material 33 shown
in FIGS. 2 and 3, which sheet that has a plurality of
bend-controlling displacements, generally designated 35, populated
along the bend lines. The article in the illustrated embodiment is
a NEMA-3R, 4, or 12 electrical enclosure which has been configured
to withstand and pass the NEMA standards rain test (e.g., one hour
rain test with no water intrusion on top and sides).
[0034] For the purposes of the present discussion, fluid-resistance
refers to the increased resistance of fluid flow through the sheet
material past the displacements in the vicinity of the bend line.
For example, the bend lines of the enclosure 30 are fluid resistant
and therefore resist the intrusion of fluids into the enclosure in
conformance with NEMA-3R standards. Thus, rainwater and weather
elements will not pass through displacements from one side of the
sheet material to the other and into the enclosure when subjected
to typical weather conditions. Fluid-resistance may also refer to
an inappreciable amount of fluid loss along the bend line past the
displacements. For example, acoustic sound tests may be utilized to
measure fluid loss from HVAC and other ducting systems to determine
whether the systems conform to industry standards of quality and/or
efficiency.
[0035] One will appreciate, however, that the methods and sheets of
the present invention are suitable for a wide variety of products
including, but not limited to, electronic component chasses,
automotive components, transport components, construction
components, appliance parts, truck components, RF shields, HVAC
components, aerospace components, toys, outdoor equipment, boats,
recreational equipment, and more.
[0036] In particular, the teachings of the present application are
applicable to a wide variety of 3D products and articles that are
formed by folding 2D sheet materials, which products require bends
where some degree of pressure tightness is required. For example,
the methods and sheets disclosed herein are equally suited for use
in refrigerator side-walls and automotive structural components
where fluid-resistance is desired.
[0037] In many aspects, the sheet materials of the present
invention are similar to those disclosed by U.S. Pat. No.
6,481,259, U.S. Pat. No. 6,877,349, U.S. Pat. No. 7,152,449, U.S.
Pat. No. 7,152,450, U.S. patent application Ser. No. 10/821,818
(Pub. No. 2005/0005670), U.S. Pat. No. 7,032,426, U.S. Pat. No.
7,263,869, U.S. patent application Ser. No. 10/985,373 (Pub. No.
2005/0061049), U.S. patent application Ser. No. 11/357,934 (Pub.
No. 2006/0261139), U.S. Pat. No. 7,374,810, U.S. patent application
Ser. No. 11/384,216 (Pub. No. 2006/0207212), U.S. Pat. No.
7,350,390, U.S. patent application Ser. No. 11/374,828 (Pub. No.
2006/0213245), U.S. patent application Ser. No. 11/180,398 (Pub.
No. 2006/0021413), U.S. patent application Ser. No. 11/290,968
(Pub. No. 2006/0075798), U.S. patent application Ser. No.
11/411,440 (Pub. No. 2007/0113614), U.S. Provisional Patent
Application No. 60/665,577, U.S. patent application Ser. No.
11/386,463 (Pub. No. 2006/0277965), and U.S. Provisional Patent
Application No. 60/854,846, the entire contents of which patents
and patent applications are incorporated herein for all purposes by
this reference.
[0038] As described in the aforementioned '450 patent, when slits
are formed with a kerf by cutting and similar processes, there is a
tendency for the material on opposite sides of the bend line to
open up during bending and separate or create a gap upon bending
despite the edge-to-face engagement described therein. The
resulting gap allows "light" to pass through and thus provide
evidence of poor sealing and permeability in a particular location.
For example, daylight, ambient, laser, and/or other forms of light
may be used to visually fluid resistance along the bend line by
shining the light against the bend line after bending. Noticeable
traces of laser light may be visible through the displacements in
all but the most fluid resistant seals (e.g., such seals passing
NEMA-3R, 4, or 12 tests and/or other industry standards of fluid
resistance), while significant traces of less intensity light
sources may be clearly discernable in cases of poor sealing. As
will be described in detail below, the approach in the illustrated
embodiment is to configure a displaced tongue 37 of displacement 35
such that the tongue will minimize or shut out "light" along the
bend line when the sheet of material is bent into a
three-dimensional article. This approach results in the closing of
the gaps or an absence thereof such as may be required by
particular applications.
[0039] Referring to FIG. 2, sheet of material 33 is prepared by
forming at least one bend-controlling displacement 35 in the
thickness direction of the sheet of material in a manner similar to
the methods described in the above-mentioned patents and
applications. One or more bend-controlling displacements are formed
in the sheet of material to define bend line 32. In the illustrated
embodiment, the displacements are formed on one side of the bend
line. In some instances, such configuration may provide a more
appealing visual appearance. One will appreciate, however, that the
bend-controlling displacements may also be formed on alternate
sides of the bend line.
[0040] Generally, the displacement is formed by a lance impacting
the sheet of material and displacing at least a portion of the
corresponding tongue into an opposing cavity in a relatively
conventional manner. The bend-controlling displacement thus formed
includes a tongue displaced at least partially below the plane
formed by adjacent surface of the sheet of material (e.g., opposed
sheet surface 44. An end of tongue 37 proximate the bend line is
completely sheared such that a sheared edge 39 is at least
displaced partially below a plane defined by the original sheet of
material (see, e.g., FIG. 6).
[0041] In one embodiment, the sheared edge extends below the
opposed sheet surface a distance that is approximately 65% to 100%
the thickness of the material, preferably approximately 70% to 96%,
and more preferably approximately 70% to 85%. For example, in one
embodiment in which the sheet of material is 16 gauge mild steel,
the sheared edge has a maximum z-depth of approximately 0.095' to
0.110'' wherein z-depth is the total measurement material thickness
and displacement distance (see, e.g., FIG. 6A).
[0042] Accordingly, a portion of a periphery 40 of the
bend-controlling displacement proximate the bend line defines a
sheared face 42 directed toward an opposed sheet surface 44 in the
sheet of material on an opposite side of the bend line. The
plurality of bend-controlling displacements 35 are formed in the
sheet of material with sheared edge 39 extending along respective
sheared face 42. In the illustrated embodiment, the
bend-controlling displacements are all located along one side of
the bend line. For better understanding, FIGS. 4B and 5B are
enlarged schematic views an exemplary configuration of
bend-controlling displacements.
[0043] The opposed sheet surface is not to be confused with the
opposed face. As shown in FIGS. 6A and 6B, sheared edge 39 extends
toward and is adjacent to an end of opposed sheet surface 44.
Opposed face 46 is located at an end of the opposed sheet surface.
In contrast, sheared face 42 is located on a distant end of tongue
37. Although the opposed sheet surface has a face surface at an
end, sheared face herein refers to the face surface at the sheared
end of the bend-controlling displacement or tongue. Opposed sheet
surface herein refers to the panel or portion of the sheet of
material on an opposite side of the bend line from the
bend-controlling displacement. Opposed face herein refers to the
face surface at the end of the opposed sheet surface.
[0044] The shearing of the displacement creates a vertical
displacement in the thickness direction of the sheet of material.
The bend-controlling displacement defines an opposed face 46
opposite each sheared face 42. Viewed from the side, the sheared
face and opposed face may in actuality be displaced not vertically
but horizontally and such that they are offset from each other.
This is due to the fact that the sheared face is displaced and
extends below the plane defined by the opposed face and may pull
away from the opposed face during displacement. In one embodiment,
the sheared face and opposed face are configured and positioned
such that bending of the sheet of material about the bend line
produces edge-to-face engagement of the sheet of material.
[0045] Bend-controlling displacement 35 has a substantially
oval-shape and includes periphery 40 with end portions 47 and a
crown portion 49 extending between the end portions. In contrast to
conventional displacements, the crown portion of the
bend-controlling displacement has an arcuate or curved profile. The
crown portion may have a large radii arc such that the curve of the
crown portion is gradual.
[0046] The curve of the crown portion also plays a noteworthy role
in forming the fluid-resistance of the bend line. It has been found
that the curve of the crown portion controls the forces in the
sheet of material such that the material around the sheared edge
and face is pulled into substantial sealing engagement to close out
the "light." That is, the arched crown portion promotes close
abutment along the length of the displacement such that, once bent,
minimal or no "light" passes by or through the displacement thus
evidencing fluid-resistance (shown in FIG. 5A). In part, the
relatively large curvature of the crown promotes elastic
deformation of the opposing face and thus appears to contribute to
the opposing face to "spring" against the crown.
[0047] As shown in FIGS. 10 and 11, the radius of the curvature may
vary. Depending on the application, the crown portion may have a
relatively small radius of curvature or the crown portion may be
relatively large radius of curvature such the sheared face is only
slightly convex. If the profile of the crown portion is too high,
meaning the radius of curvature is not large enough, the outermost
portion of the sheared face may push away the sheet of material and
prevent sealing against the sheared edge.
[0048] Preferably, the bend-controlling displacement includes a
second crown portion opposite the first crown portion which mirrors
the first crown portion such that it has the same or substantially
equal radius of curvature and shape. Such symmetric configuration
would improve tool life in that punches used to form the
displacements may be rotated 180.degree. (e.g., rotated about a
vertical axis) thereby almost doubling tool life, and may also be
flipped 180.degree. (e.g., turned upside down) thereby almost
quadrupling tool life. A joggle zone 51 connects an unsheared
portion 53 of a periphery of bend-controlling displacement 35 to
sheet material 33.
[0049] In the illustrated embodiment, the end portions have an
arcuate profile similar to the crown portion except that the radius
of curvature of the end portions is substantially smaller than the
radius of curvature of the crown portion. The end portions are a
small radii arc, meaning, the end portions have a tight curvature.
For example and with reference to FIG. 3A, the centers of the radii
of curvature of the end portions are located on the displacement.
Preferably the radii of curvature of the end portions are within an
order of magnitude of the thickness of the sheet material. For
example, the end portion radii of curvature is preferably 1.5 T and
the diameter is 3.0 T where "T" is the thickness dimension of the
sheet material. In contrast, the crown portions have much larger
radii of curvatures. For example, the centers of radii of curvature
of the crown portions are located outside of the displacement, and
may be multiple orders of magnitude greater than the thickness of
the sheet material.
[0050] As shown in FIGS. 10 and 11, the radii of curvature may vary
substantially, and the radii of curvature of the end portions may
be modified independently of the radius of the crown portion. As
discussed, the crown may be adjusted for elastic behavior with
softer springing action of the material, and in particular
springing action of the opposed face against the sheared edge,
during and after bending.
[0051] Preferably, the bend-controlling displacement 35 includes
transition zones 54 located between the crown portion 49 and each
end portions 49. The transition zones have radii of curvature
intermediate the radii of curvature of the end portions and the
crown portion. Thus, the transition zones serve to transition
periphery 40 between the larger radius of curvature of the crown
portions and smaller radius of curvature of the end portions.
[0052] It has been found that a smoother transition between crown
portion 49 and a respective end portion 47 corresponds to improved
sealing of sheared face 42 when material 33 is bent. Put another
way, providing a smaller and more gradual rate of change of the
radius of curvature between the crown portion and respective end
portions improves fluid-resistant sealing along the bend after the
sheet of material has been bent along the bend line.
[0053] The transition zones are also configured and dimensioned to
accommodate the shift between primarily elastic and plastic
deformation by producing even contact pressure by developing a zone
in which the opposed face successfully follows the curve of the
crown's periphery. Gradually diminishing the radii of curvature
along the transition zone between the crown and the end portions
promotes improved conformance and transition of plastic and elastic
deformation and produces a better seal.
[0054] Crown portions 49 and end portions 47 form the primary shape
of periphery 40 of the bend-controlling displacement. Each end
portion 47 includes a portion of sheared face 42 and a portion of
joggle zone 51. Likewise, joggle zone 51, transition zones 54, and
end portions 47 form the peripheral edge structure of the
displacement. In the illustrated embodiment, each transition zone
extends around the periphery of the bend-controlling displacement
within approximately 5.degree. and 15.degree. of a longitudinal
axis of the displacement with respect to a center of the
displacement as shown in FIG. 8 (see, e.g., angles "A" and "B"
respectively). One will appreciate, however, that the actual
dimensions and location of the transition zone may vary
tremendously depending upon the respective radii of curvature of
the crown and end portions. Moreover, the transition zones have
regional or localized characteristics but might not have distinct
structural boundaries with respect to the crown and end portions.
In particular, the opposed face material may displays overlapping
behavior between the zones as each fades into an adjacent zone.
[0055] Sheared face 42 extends along the crown portion, through the
transition zones and into the end portions. The sheared face
preferably extends within approximately 0-80.degree., preferably
0.degree.-60.degree., more preferably 0.degree.-40.degree., of the
longitudinal axis of the displacement with respect to a radial
center of the end portion as also shown in FIG. 8 (see, e.g., angle
"C"). One will appreciate that the amount the sheared face extends
may vary.
[0056] The actual location of shear termination may be adjusted by
varying the configuration of tooling used to form the
displacements. FIG. 9 depicts the boundaries of the lance "L" which
displaces the bend-controlling displacement into cavity "C"
opposing the lance. The peripheral shape of the lance largely
corresponds to the shape of tongue 37, while the peripheral shape
of the cavity largely corresponds to the shape of the sheared edge
39 and joggle zone 51. The edges of the lance and cavity thus form
the shape of the bend-controlling displacement. In the illustrated
embodiment, the distance between the lance edge and cavity edge
along the crown and closes to the bend line is approximately 10% of
the thickness of the sheet material, which dimension is generally
understood to produce shear. The distance between the lance edge
increases along the end portions. It has been observed that shear
terminates when the distance expands to approximately 25% of the
thickness of the sheet material. By adjusting the curvature of the
lance and cavity shapes, it is possible to adjust the location of
the 25% threshold and thus is possible to adjust the location of
shear termination.
[0057] With continued reference to FIG. 9, the figure also
illustrates the various radii of curvature found in the transition
zone. For example, the radii of curvatures of the lance's crown and
end portions are designated R.sub.LC and R.sub.LE, respectively,
where the designation refers to "lance-crown radius" and
"lance-end-portion radius, while the radii of curvature of the
lance's transition zone are designated R.sub.LT1, R.sub.LT1, . . .
R.sub.LT5, respectively. FIG. 9 also illustrates that the various
positions of the centers of curvature.
[0058] In the bent position when the sheet of material is folded
over the bend line, bend-controlling displacements 35 fold into a
closed position such that no "light" or gaps remain along the bend
line. In particular, the sheared edge conforms to the shape of the
tongue. During bending, a balancing of the plastic behavior along
the ends and the elastic behavior in the middle promotes
face-to-surface contact between sheared face 42 and opposed sheet
surface 44 such that the sheet material is substantially
fluid-resistant along the bend line. As best seen in FIG. 5, the
face and sheet abut each other to close off the gaps which may be
apparent with conventional slitting techniques.
[0059] In one embodiment, each of the bend-controlling
displacements is formed with a pair of bending straps 56 in the
sheet of material which intersect bend line 32. The
bend-controlling displacements are formed with bending straps on
each end such that a respective sheared face 42 extends between the
bending straps. The bend straps are configured and positioned such
that bending of the sheet of material subjects straps 56 to tension
such that sheared face 42 closely abuts against opposed sheet
surface 44 when the sheet of material is bent. In particular, as
the two panels of the sheet on each side of the bend line are
folded, the opposed sheet surface is pulled towards and conforms
against the sheared face and sheared edge. As best seen in FIG. 5,
it is desirable to configure the bend-controlling displacements
such that the bending straps pull over and against the outer ends
of the displacements during bending, as illustrated with arrows
"T". In the outer ends of each displacement the periphery
transitions from a sheared edge to a continuous web of material. In
this manner, these outer ends are substantially sealed when the
sheet of material is bent.
[0060] In one embodiment, when sheet of material 33 is bent along
the bend line, the sheared gap is closed by sealing of material
along sheared edge 39. In the bent position, the sides of the
sheared edge are in contact with bending straps 56. The central
portion of the sheared edge is also in contact with opposed surface
44. Thus, the bending of the sheet seals the opposed surface to the
sheared face when the sheet of material is bent. In one embodiment,
the seal is substantially formed by close abutment of the sheared
face to the opposed surface. When the abutment is substantially
uniform along the sheared face the seal becomes tighter.
[0061] Further, and with reference to FIG. 5, the fluid resistant
seal is formed with no use of sealing materials. Instead the seal
is formed primarily by virtue of the close and substantially
uniform abutment of materials formed during bending and without the
use of extra materials. Sealing materials refers to conventional
sealing materials as understood in the art. Sealing materials also
refers to other devices or materials formed merely to aid in the
sealing function.
[0062] In one embodiment, the lance is formed with a rooftop and
crown whereby a central portion of the lance is flat and ends
extending longitudinally from the central portion are sloped
upward. When forming the displacements with such a lance the onset
of shearing in the joggle zone can be further controlled. Such a
lance structure further reduces stamping forces and the possibility
of "light" forming at an end of the lance.
[0063] In some applications it may be desirable to further insure
that the bend in the sheet of material is fluid-resistant or even
fluid-tight. Accordingly, in one embodiment a continuous,
preferably flexible, layer of coating material 58 is adhered to the
sheet of material across the bend-controlling displacements (see,
e.g., FIG. 6). The coating layer may be applied prior to lancing or
bending such that it remains substantially intact (e.g., not
significantly chipped and/or cracked) after the bending. In the
alternative, the sheet of material may be folded into a
three-dimensional structure and thereafter treated with a coating
layer along the bend lines. Suitable materials for the layer of
coating include, but are not limited to, paint, plastics, grease,
and relative viscous gel compounds. In an alternative embodiment
the bend-controlling displacement or sheet of material includes
other forms, structures, or shapes, formed separately or
monolithically formed, to aid in the sealing function.
[0064] The method of forming a three-dimensional structure in
accordance with the present invention can now be described. A
two-dimensional sheet of material is first prepared as described
above. In particular, at least one bend-controlling displacement is
formed in the thickness direction of the sheet of material with a
substantially oval shape at a sheet preparation station. The
bend-controlling displacement may be formed using CNC machining,
stamping, punching, or the like, as is discussed in the
above-mentioned patents and patent applications.
[0065] The bend-controlling displacement includes a periphery with
end portions 47 and curved crown 49 extending between the end
portions proximate the bend line. The bend-controlling displacement
is sheared along a portion of the periphery such that a sheared
face extends along the crown portion and into the end portions. The
sheared face faces an opposed sheet surface in the sheet of
material on an opposite side of the bend line.
[0066] As described above, the curved crown portion is dimensioned
to produce face-to-surface engagement between the sheared face and
the opposed sheet surface. Accordingly, when the structure is
formed and the sheet is bent along the bend lines, the
face-to-surface engagement creates a fluid-resistant seal along the
bend line. Likewise, the displacement may be configured with
bending straps to seal to portions of the sheared edge.
[0067] Next, the sheet of material is bent along successive bend
lines. This may be done in the same station or at a different
station. Moreover, additional components and subassemblies may be
fastened to the structure before or after bending. Such components
may also be placed on the sheet of material and wrapped inside the
sheet of material during the bending process.
[0068] As will be understood from the above description, the
dimensions of the bend-controlling displacement, particularly the
crown portion, end portions, transition zones, and z-distance may
be modified to suit application needs. The exact configuration will
depend on several characteristics including, but not limited to,
the degree of fluid-resistance required, the material
characteristics, aesthetic concerns, and the maximum desired effort
in bending.
[0069] After bending into the three-dimensional structure, the
structure may be fastened with a fastener 60 and finished at a
finishing station. As described above, the structure may be treated
with a sealing or layer of coating to further enhance
fluid-resistance. The structure may also be fastened with
conventional fasteners or welding.
[0070] The above-described method allows for precision-folding of
three-dimensional structure with a fluid-resistant bend line from a
two-dimensional sheet of material. The sheet of material and method
therefor in accordance have other advantages over conventional
slitting techniques. The method allow for preparing a
two-dimensional for folding into a fluid-resistant
three-dimensional structure without the need for complex fluid
sealing processes.
[0071] 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 present
invention with reference to the positions of such features as
displayed in the figures. However, any physical orientation is
possible, so these terms are used only as a matter of convenience
and should not be construed as absolute.
[0072] The foregoing descriptions of specific 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
teaching. The embodiments were chosen and described in order to
best explain the principles of the invention and its practical
application, to thereby enable others skilled in the art to best
utilize the invention and various embodiments with various
modifications as are suited to the particular use contemplated. It
is intended that the scope of the invention be defined by the
Claims appended hereto and their equivalents.
* * * * *