U.S. patent application number 13/845875 was filed with the patent office on 2013-10-31 for three-dimensional cellular light structures weaving by helical wires and the manufacturing method of the same.
The applicant listed for this patent is Ki Ju KANG, Yong Hyun LEE. Invention is credited to Ki Ju KANG, Yong Hyun LEE.
Application Number | 20130284858 13/845875 |
Document ID | / |
Family ID | 37810923 |
Filed Date | 2013-10-31 |
United States Patent
Application |
20130284858 |
Kind Code |
A1 |
KANG; Ki Ju ; et
al. |
October 31, 2013 |
THREE-DIMENSIONAL CELLULAR LIGHT STRUCTURES WEAVING BY HELICAL
WIRES AND THE MANUFACTURING METHOD OF THE SAME
Abstract
A three-dimensional cellular light structure formed of
continuous wire groups. For example, six orientational helical wire
groups are intercrossed in a three-dimensional space and form a
uniform pattern. In a manufacturing method, a frame assembly of
rectangular frames and connection support bars is used. The method
includes arranging and fixing first axis wires on the frames,
connecting the frames by connection support bars, and assembling
second axis wires to make a three-dimensional cellular light
structure. The intersection points of the wires may be bonded. It
can be a fiber-reinforced composite material by filling at least
part of an internal empty space of the structure.
Inventors: |
KANG; Ki Ju; (Chonnam,
KR) ; LEE; Yong Hyun; (Chonnam, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KANG; Ki Ju
LEE; Yong Hyun |
Chonnam
Chonnam |
|
KR
KR |
|
|
Family ID: |
37810923 |
Appl. No.: |
13/845875 |
Filed: |
March 18, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12516967 |
Jun 11, 2009 |
8418730 |
|
|
PCT/KR2007/002367 |
May 15, 2007 |
|
|
|
13845875 |
|
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Current U.S.
Class: |
245/2 |
Current CPC
Class: |
E04B 1/19 20130101; B21F
3/02 20130101; B21F 27/12 20130101; B21F 27/005 20130101; D03D
25/005 20130101 |
Class at
Publication: |
245/2 |
International
Class: |
B21F 27/00 20060101
B21F027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 29, 2006 |
KR |
10-2006-0119233 |
Claims
1. A three-dimensional cellular light structure manufactured by
assembling 1st, 2nd, 3rd, 4th, 5th and 6th-axis wires in
three-dimensional space; wherein the 1st, 2nd, 3rd, 4th, 5th and
6th-axis wires have a helical shape; and wherein the 1st, 2nd and
3rd-axis wires are assembled to form a plurality of two-dimensional
Kagome planes and the 4th, 5th and 6th-axis wires are assembled in
out-of plane directions on two-dimensional Kagome planes consisted
of the 1st, 2nd and 3rd-axis wires.
2. The three-dimensional cellular light structure according to
claim 1 wherein the 1st, 2nd and 3rd-axis wires are assembled to
form the two-dimensional Kagome planes of A, B and C layers in
sequence from the bottom, and the wires in one layer are arranged
to be constantly shifted from the wires on adjacent layers so as to
maintain position deviations in horizontal and vertical directions
with respect to adjacent layers.
3. The three-dimensional cellular light structure according to
claim 2, wherein the wires in each layer are arranged so as to
maintain a horizontal position deviation l.sub.x and a vertical
position deviation l.sub.y between two adjacent layers, and the
wires in each layer form the two-dimensional Kagome planes, where
lx=P/2,ly= {square root over (3)}P/6, P=wire pitch.
4. The three-dimensional cellular light structure according to
claim 2, wherein the two-dimensional Kagome planes having the
layers A, B and C are repeatedly laminated in a manner of A, B, C,
A, B, C, Y, and the distance between two adjacent layers is H=
{square root over (3)}P/3.
Description
RELATED APPLICATIONS
[0001] The present application is a divisional under 37 C.F.R.
.sctn.1.53(b) of prior application Ser. No. 12/516,967, filed Jun.
11, 2009, by Ki Ju KANG and Yong Hyun LEE entitled
THREE-DIMENSIONAL CELLULAR LIGHT STRUCTURES WEAVING BY HELICAL
WIRES AND THE MANUFACTURING METHOD OF THE SAME, which is a U.S.C.
.sctn.371 National Phase conversion of PCT/KR2007/002367, filed May
15, 2007, which claims benefit of Korean Application No.
10-2006-0119233, filed Nov. 29, 2006, the entire disclosure of
which is hereby incorporated by reference. The PCT International
Application was published in the English language.
TECHNICAL FIELD
[0002] The present invention relates to a three-dimensional
cellular light structure formed of continuous wire groups and a
method of manufacturing the same. More particularly, the present
invention relates to a three-dimensional light structure similar to
an ideal Kagome truss structure having greatly improved mechanical
properties such as strength and rigidity, and a method of
mass-producing the same in a cost-effective manner.
BACKGROUND ART
[0003] Conventionally, a metal foam has been known as a material
similar to a cellular light structure. The metal foam is
manufactured by producing bubbles inside a metal of liquid or
semi-solid state (closed cell-type), or by casting the metal into a
mold made of a foaming resin such as sponge (open cell-type).
However, these metal foams have relatively poor mechanical
properties such as strength and rigidity. In addition, due to its
high manufacturing cost, it has not been used widely in practice,
except for a special purpose such as in aerospace or aviation
industries.
[0004] As a substitute material for the above mentioned metal
foams, open cell-type light structures with periodic truss cells
have been suggested. This open cell-type light structure is
designed so as to have an optimum strength and rigidity through
precise mathematical and mechanical analysis, and therefore it has
good mechanical properties. A typical truss structure is
exemplified by the Octet truss where regular tetrahedrons and
regular octahedrons are combined (See R. Buckminster Fuller, 1961,
U.S. Pat. No. 2,986,241). Each element of the truss forms an
equilateral triangle and thus it is advantageous in terms of
strength and rigidity. Recently, as a modification of the Octet
truss, the Kagome truss has been reported (See S. Hyun, A. M.
Karlsson, S. Torquato, A. G. Evans, 2003, Int. J. of Solids and
Structures, Vol. 40, pp. 6989-6998).
[0005] Referring to FIG. 1, when the two-dimensional Octet truss
101 and the two-dimensional Kagome truss 102 are compared, a unit
cell 102a of the Kagome truss 102 has an equilateral triangle and a
regular hexagon mixed in each face, dissimilar to a unit cell 101a
of the Octet truss 101.
[0006] FIGS. 2 and 3 show a single layer of the three-dimensional
Octet truss 201 and the three-dimensional Kagome truss 202,
respectively. Comparing a unit cell 201a of the three-dimensional
Octet truss 201 with a unit cell 202a of the three-dimensional
Kagome truss 202, one of the significant features of the
three-dimensional Kagome truss 202 is that it has low anisotropic.
Therefore, the structural materials or other materials based on the
Kagome truss 202 have almost a uniform mechanical and electrical
property regardless of its orientation.
[0007] Several processes have been used for manufacturing a
truss-type cellular light structure. First, a truss structure is
formed of a resin, and a metal is cast using the truss structure as
a mold, i.e., investment casting (See S. Chiras, D. R. Mum, N.
Wicks, A. G. Evans, J. W. Hutchinson, K. Dharmasena, H. N. G.
Wadley, S. Fichter, 2002, International Journal of Solids and
Structures, Vol. 39, pp. 4093-4115). Second, a metallic mesh is
formed by punching periodic holes in a thin metal plate, and a
truss layer is formed by bending the metallic mesh. Then, face
sheets are bonded to the upper and lower portions of the truss
layer as a core of a sandwich panel (See D. J. Sypeck and H. N. G.
Wadley, 2002, Advanced Engineering Materials, Vol. 4, pp. 759-764).
Here, in the case where a two-layered structure is to be
fabricated, another truss intermediate layer is placed on the upper
face sheet and another upper face sheet is positioned again
thereon. By repeating the same procedure, multi-layered structure
can be fabricated. In the third method, wire nets are first woven
using two orientational wires perpendicular to each other, and then
the wire nets are laminated and bonded (See D. J. Sypeck and H. G.
N. Wadley, 2001, J. Mater, Res., Vol. 16, pp. 890-897).
[0008] As for the first method, its complicated manufacture process
leads to a high manufacture cost. Only metals having a good
castability can be applied and consequently it has limited
applications. The resultant material tends to have casting defects
and deficient strength. As for the second method, the process
punching periodic holes in thin metal plate leads to loss of
material. Moreover, even though there is no specific problem in
manufacturing a sandwiched plate having a single-layered truss, the
truss cores and face sheets must be laminated and bonded repeatedly
so as to manufacture a multi-layered structure, thereby producing
many bonding points which results in disadvantages in terms of
bonding cost and strength.
[0009] As for the third method, basically the formed truss has no
ideal regular tetrahedron or pyramid shape and thus has an inferior
mechanical strength. Similar to the second method, lamination and
bonding are must be involved for manufacturing a multi-layered
structure and therefore disadvantageous in respect of bonding cost
and strength.
[0010] FIG. 4 shows a light structure manufactured by the third
method, which is formed by laminating wire nets. This method is
known to be able to reduce the manufacturing cost, but wires of two
orientations are woven like fabrics, and therefore it cannot
provide an ideal structure having as good mechanical strength as in
the above-described three-dimensional Octet truss 201 or the
three-dimensional Kagome truss 202. Accordingly, it has
disadvantages in terms of the cost and the strength, due to lots of
portions to be bonded.
[0011] Meanwhile, a common fiber reinforced composite material is
manufactured in the form of thin two-dimensional layer, which is
laminated when a thick material is required.
[0012] However, in this case, due to delamination phenomenon
between the layers, its strength tends to be deteriorated. In order
to prevent the delamination, the fiber is woven into a
three-dimensional structure from the beginning, and then a matrix
such as resin, metal, or the like is combined with the structure.
FIG. 5 shows a perspective view of the woven fibers in this
three-dimensional fiber reinforced composite material. Instead of
fibers, a material such as a metallic wire having a high stiffness
can be woven into a three-dimensional cellular light structure as
shown in FIG. 5. However, it also does not have the above-described
ideal Octet or Kagome truss structure, and it has a decreased
mechanical strength and more anisotropic material properties.
Consequently, the composite material formed of the
three-dimensional woven-fibers comes to have inferior mechanical
properties.
[0013] In view of the aforementioned shortcomings, the inventors of
the present invention have devised a three-dimensional cellular
light structure which is manufactured in a uniform pattern similar
to the ideal Kagome truss or Octet truss by intercrossing six-axial
continuous wire groups at 60 degrees or 120 degrees of angles in a
space, and a manufacturing method thereof, which is disclosed in
Korean Patent Publication No. 10-2006-0095968 (hereinafter,
earlier-filed invention).
[0014] The three-dimensional cellular light structure manufactured
according to the earlier-filed invention has several advantages in
that it has good mechanical properties and can be mass-produced in
a cost-effective manner through continuous processes, over the
conventional methods. The inventors have made an earnest study for
improving mechanical properties relating to the rigidity and the
strength of the three-dimensional cellular light structure,
together with high efficiency, low cost and mass-productivity in
weaving method, and finally accomplished the present invention.
DISCLOSURE
Technical Problem
[0015] The present invention has been made to solve the above
problems occurring in the prior art. It is an object of the
invention to provide a Kagome truss-type three-dimensional light
structure formed of six-axial continuous helical wire groups
intercrossed at 60 degrees or 120 degrees in a space, wherein the
three-dimensional light structure can be easily manufactured in a
uniform pattern through continuous processes comprising a step of
forming a plurality of two-dimensional Kagome planes consisting of
1st, 2nd and 3rd-axis helical wires and a step of assembling 4th,
5th and 6th-axis helical wires in out-of plane directions on
two-dimensional Kagome planes consisted of the 1st, 2nd and
3rd-axis wires, and wherein close contact structure among the wires
can be realized to thereby improve the mechanical properties such
as strength, rigidity or the like. It is another object of the
invention to provide a method of mass-producing the
three-dimensional light structure in a cost-effective manner.
[0016] The three-dimensional light structure according to the
present invention is manufactured in such a manner that a
continuous wire is directly woven into a three-dimensional
structure, not in the manner that planar wire-nets are simply
laminated and bonded. Therefore, the cellular light structure of
the invention is very similar to the ideal Kagome truss, and thus
exhibits a good mechanical and electrical property.
Technical Solution
[0017] The features of the present invention for attaining the
aforementioned objects are as follows.
[0018] (1) A three-dimensional cellular light structure
manufactured by assembling 1st, 2nd, 3rd, 4th, 5th and 6th-axis
wires in three-dimensional space, wherein the 1st, 2nd, 3rd, 4th,
5th and 6th-axis wires have a helical shape, and wherein the 1st,
2nd and 3rd-axis wires are assembled to form a plurality of
two-dimensional Kagome planes and the 4th, 5th and 6th-axis wires
are assembled in out-of plane directions on two-dimensional Kagome
planes consisted of the 1st, 2nd and 3rd-axis wires.
[0019] (2) The three-dimensional cellular light structure, wherein
the 1st, 2nd and 3rd-axis wires are assembled to form the
two-dimensional Kagome planes of A, B and C layers in sequence from
the bottom, and the wires in one layer are arranged to be
constantly shifted from the wires on adjacent layers so as to
maintain position deviations in horizontal and vertical directions
with respect to the adjacent layers.
[0020] (3) The three-dimensional cellular light structure, wherein
the wires in each layer are arranged to maintain a horizontal
deviation l.sub.x and a vertical deviation l.sub.y between two
adjacent layers, and the wires in each layer form the
two-dimensional Kagome planes.
[0021] (4) The three-dimensional cellular light structure, wherein
the two-dimensional Kagome planes of the A, B and C layers are
repeatedly laminated in a manner of A, B, C, A, B, C, . . . , while
maintaining prescribed distance between two adjacent layers.
[0022] (5) A method of manufacturing a three-dimensional cellular
light structure, the method comprising:
[0023] a helical wire forming step of forming 1st, 2nd, 3rd, 4th,
5th and 6th-axis helical wires;
[0024] a two-dimensional Kagome plane forming step of forming a
plurality of two-dimensional Kagome planes by assembling the 1st,
2nd and 3rd-axis helical wires on frames of a frame assembly;
[0025] a frame laminating step of connecting and laminating the
frames by means of connection support rods; and
[0026] a step of fabricating a three-dimensional cellular light
structure by assembling the 4th, 5th and 6th-axis helical wires
into the 1st, 2nd, and 3rd-axis helical wires in each frame.
ADVANTAGEOUS EFFECTS
[0027] According to the present invention relating to a
three-dimensional cellular light structure and a method of
manufacturing the same, the 1st, 2nd and 3rd helical wires are
assembled on frames to form a plurality of two-dimensional Kagome
planes, the 4th, 5th and 6th wires are assembled with the wires in
the two-dimensional Kagome planes to form the three-dimensional
cellular light structure. Therefore, the three-dimensional cellular
light structure consisting of continuous wires can be easily
manufactured, thereby enabling a mass production and cost-down.
[0028] In addition, since the continuous wires of the
three-dimensional cellular light structure of the present invention
have a helical shape, the three dimensional cellular light
structure can be assembled by rotating insertion of the
helical-shaped wires and also close contacts between the wires are
enhanced without causing any damage to the intended truss
structure. Accordingly, desired mechanical properties can be
ensured even if the three-dimensional cellular light structure is
not further subject to post-processing such as welding, brazing,
soldering, liquid, or the like.
DESCRIPTION OF DRAWINGS
[0029] FIG. 1 is a two-dimensional view comparing the conventional
two truss structure, i.e., the Octet truss and Kagome truss;
[0030] FIG. 2 shows a plane view and a side view of a single layer
in the conventional three-dimensional Octet truss, and a
perspective view of a unit cell thereof;
[0031] FIG. 3 shows a plane view and a side view of a single layer
of the conventional three-dimensional Kagome truss, and a
perspective view of a unit cell thereof;
[0032] FIG. 4 is a perspective view of a light structure
manufactured by laminating wire nets according to the conventional
method;
[0033] FIG. 5 is a perspective view and a detailed view showing a
three-dimensional fiber reinforced composite material fabricated by
weaving a fiber according to the conventional method;
[0034] FIGS. 6 through 12 are views for illustrating the
earlier-filed invention of the present invention;
[0035] FIG. 6 is a plane view of a wire-woven network formed of
three axial-parallel wire groups and similar to the two-dimensional
Kagome truss in FIG. 1.
[0036] FIG. 7 is a perspective view of a unit cell corresponding to
the portion A in FIG. 6 when the two-dimensional structure of FIG.
6 is transformed into a structure similar to the three-dimensional
Kagome truss in FIG. 3;
[0037] FIG. 8 is a perspective view of a unit cell of the Kagome
truss of FIG. 3, which is formed of six-axial wires;
[0038] FIG. 9 is a perspective view showing a three-dimensional
cellular structure of Kagome truss type, which is formed of
six-axial wire groups;
[0039] FIG. 10 is a perspective view of the structure of FIG. 9 as
seen from different angles;
[0040] FIG. 11 is a perspective view of a vertex of the regular
tetrahedron formed by three-axial wire groups in the structure of
FIG. 9, which is seen from the front of the vertex;
[0041] FIG. 12 is a perspective view of unit cells formed by a
different wire-intercrossing mode in FIG. 11;
[0042] FIGS. 13 through 39 show an embodiment of the present
invention;
[0043] FIG. 13 is a picture of a helical wire;
[0044] FIG. 14 is a picture of a plurality of wires formed in a
helical shape;
[0045] FIG. 15 is a picture of a twisting machine for forming the
helical wire;
[0046] FIG. 16 is a picture of helical wires for the 1st, 2nd, 3rd,
4th, 5th, and 6th-axes;
[0047] FIG. 17 is a picture of a frame assembly for assembling the
helical wires;
[0048] FIG. 18 is a picture showing the 1st, 2nd and 3rd-axis wires
assembled on a frame of the frame assembly to form the
two-dimensional Kagome plane;
[0049] FIG. 19 is a picture showing two layers of the
two-dimensional Kagome planes assembled on frames of the frame
assembly;
[0050] FIG. 20 is a picture showing the 4th, 5th and 6th-axis wires
assembled with the two-dimensional Kagome planes;
[0051] FIG. 21 is a picture of a completed three-dimensional
cellular light structure with the frames removed;
[0052] FIG. 22 is a plane view of the assembled 1st and 2nd-axis
wires;
[0053] FIG. 23 is a plane view showing the step of assembling the
3rd-axis wires;
[0054] FIG. 24 is a plane view of a single layer of the
two-dimensional Kagome plane formed of the 1st, 2nd and 3rd-axis
wires;
[0055] FIGS. 25 and 26 are a plane view and a picture showing the
single layer of the two-dimensional Kagome plane assembled to the
frame;
[0056] FIG. 27 is a plane view showing a method of laminating the
two-dimensional Kagome planes of A, B, C layers;
[0057] FIGS. 28 and 29 are a perspective view and a picture showing
two layers of the two-dimensional Kagome plane with the frames;
[0058] FIG. 30 is a perspective view of two layers of the
two-dimensional Kagome plane with the frames removed;
[0059] FIG. 31 is a perspective view of three layers of the
two-dimensional Kagome plane with the frames;
[0060] FIG. 32 is a perspective view of three layers of the
two-dimensional Kagome plane with the frame removed;
[0061] FIG. 33 is a plane view and a side view showing the step of
assembling the 4th-axis wires with the 1st, 2nd and 3rd-axis wires
in the two-dimensional Kagome planes;
[0062] FIG. 34 is a plane view and a side view showing the step of
assembling the 5th-axis wires with the 1st, 2nd, and 3rd-axis wires
in the two-dimensional Kagome plane;
[0063] FIG. 35 is a plane view and a side view showing the step of
assembling the 6th-axis wires with the 1st, 2nd, and 3rd-axis wires
in the two-dimensional Kagome plane;
[0064] FIG. 36 is a perspective view showing the step of assembling
the last wire of the six axes wires;
[0065] FIG. 37 is a perspective view showing the step of assembling
the last wire of the six axes wires, when seen from a moving
direction of the last wire;
[0066] FIG. 38 is a perspective view of the final structure after
the 1st, 2nd, 3rd, 4th, 5th and 6th-axis wires are completely
assembled;
[0067] FIGS. 39 and 40 are pictures of the final structure after
the 1st, 2nd, 3rd, 4th, 5th and 6th-axis wires are completely
assembled;
[0068] FIG. 41 is a flowchart outlining processes for manufacturing
the three-dimensional cellular light structure formed of wires
according to the earlier-filed invention;
[0069] FIG. 42 is a flowchart out lining processes for
manufacturing the three-dimensional cellular light structure formed
of wires according to an embodiment of the present invention.
MODE FOR INVENTION
[0070] The features of the present invention for attaining the
aforementioned objects are as follows.
[0071] (1) A three-dimensional cellular light structure
manufactured by assembling 1st, 2nd, 3rd, 4th, 5th and 6th-axis
wires in three-dimensional space, wherein the 1st, 2nd, 3rd, 4th,
5th and 6th-axis wires have a helical shape, and wherein the 1st,
2nd and 3rd-axis wires are assembled to form a plurality of
two-dimensional Kagome planes and the 4th, 5th and 6th-axis wires
are assembled in out-of plane directions on two-dimensional Kagome
planes consisted of the 1st, 2nd and 3rd-axis wires.
[0072] (2) The three-dimensional cellular light structure, wherein
the 1st, 2nd and 3rd-axis wires are assembled to form the
two-dimensional Kagome planes of A, B and C layers in sequence from
the bottom, and the wires in one layer are arranged to be
constantly shifted from the wires on adjacent layers so as to
maintain position deviations in horizontal and vertical directions
with respect to adjacent layers.
[0073] (3) The three-dimensional cellular light structure, wherein
the wires in each layer are arranged to maintain a horizontal
deviation l.sub.x and a vertical deviation l.sub.y between two
adjacent layers, and the wires in each layer form the
two-dimensional Kagome planes.
[0074] (4) The three-dimensional cellular light structure, wherein
the two-dimensional Kagome planes of the A, B and C layers are
repeatedly laminated in a manner of A, B, C, A, B, C, . . . , while
maintaining prescribed distance between two adjacent layers.
[0075] (5) A method of manufacturing a three-dimensional cellular
light structure, the method comprising:
[0076] a helical wire forming step of forming 1st, 2nd, 3rd, 4th,
5th and 6th-axis helical wires;
[0077] a two-dimensional Kagome plane forming step of forming a
plurality of two-dimensional Kagome planes by assembling the 1st,
2nd and 3rd-axis helical wires on frames of a frame assembly;
[0078] a frame laminating step of connecting and laminating the
frames by means of connection support rods; and a step of
fabricating a three-dimensional cellular light structure by
assembling the 4th, 5th and 6th-axis helical wires into the 1st,
2nd and 3rd-axis helical wires in each frame.
[0079] Hereafter, the earlier-filed invention (Korean Patent
Publication No. 10-2006-0095968) is first described by referring to
FIGS. 6 through 12 and 41 to facilitate the understanding of the
present invention, and then an embodiment of the present invention
will be explained.
[0080] As for a structure of a three-dimensional cellular light
structure, FIG. 6 shows the two-dimensional Kagome truss
constructed by three-axial wire groups 1, 2 and 3, which is similar
to the two-dimensional Kagorne truss shown on the right side in
FIG. 1. In the two-dimensional Kagome truss woven with the wire
groups 1, 2, and 3 in three axes, two lines are intercrossed at
intersection points at 60 degrees or 120 degrees. Since each
element constituting the Kagome truss is replaced with a continuous
wire, the structure is substantially similar to the ideal Kagome
truss, except that the continuous wire makes a curvature while
intercrossing each intersection point thereof. FIG. 7 is a
three-dimensional view of the portion marked by A in FIG. 6. The
equilateral triangles facing each other are transformed to the
regular tetrahedrons, and three wires, rather than two wires, are
intercrossed at the intersection point at 60 degrees or 120
degrees. This structure is constructed by six-axial wire groups 4,
5, 6, 7, 8, and 9, which are disposed so as to have the same
orientation angle in the three-dimensional space.
[0081] The unit cell composed of the six-axial wire groups 4, 5, 6,
7, 8, and 9 comprises two regular tetrahedrons having the similar
shape, which are symmetry about a common vertex and facing each
other. The structure of the unit cell will be described in detail
below.
[0082] The wire groups 4, 5, and 6 are intercrossed with each other
in the same plane (X-Y plane) so as to constitute an equilateral
triangle. The wire 7 intercrosses the intersection point of the
wire 5 and the wire 6; the wire 8 intercrosses the intersection
point of the wire 4 and the wire 5; and the wire 9 intercrosses the
intersection point of the wire 6 and the wire 4. Here, the wire
groups 6, 9, and 7 are intercrossed with each other to form an
equilateral triangle; the wire groups 4, 8, and 9 are intercrossed
with each other to form an equilateral triangle; and the wire
groups 5, 7, and 8 are intercrossed with each other to form an
equilateral triangle.
[0083] Accordingly, the six axes wire groups 4, 5, 6, 7, 8 and 9
constitute one regular tetrahedron (a first regular
tetrahedron).
[0084] Other wire groups 4', 5', and 6' are provided in such a way
as to place above the vertex (reference vertex) of the first
regular tetrahedron, which is formed by intercrossing of the wire
groups 7, 8 and 9 located above the X-Y plane in which the wire
groups 4, 5 and 6 are intercrossed with one another. Other wire
groups 4, 5 and 6 having the same orientations as the wire groups
4, 5 and 6 are disposed such that each of them intercrosses two
wires selected from the wire groups 7, 8 and 9 to thereby form an
equilateral triangle. Accordingly, the wire groups 4', 5', 6', 7, 8
and 9 form another regular tetrahedron (a second regular
tetrahedron). As a result, the unit cell of the three-dimensional
cellular light structure 10 is composed of the regular tetrahedron
(the first regular tetrahedron) formed by the wire groups 4, 5, 6,
7, 8 and 9 and the regular tetrahedron (the second regular
tetrahedron) formed by the wire groups 4', 5', 6', 7, 8 and 9. The
first and second regular tetrahedrons are constructed respectively
at the upper and lower side of the intersection point formed by the
wire groups 7, 8 and 9 and faced with each other.
[0085] In order to form a plurality of the unit cells 10 in a
three-dimensional continuous pattern, the wires are disposed such
that an opposing regular tetrahedron can be constructed at each of
other vertexes of the regular tetrahedron, which is formed by the
wire groups 4, 5, 6, 7, 8 and 9. Therefore, a three-dimensional
cellular light truss-structure can be constructed in such a manner
that the above unit cell is repeatedly formed and combined in the
three-dimensional space.
[0086] In this way, a unit cell similar to the unit cell of the
three-dimensional Kagome truss shown in FIG. 3 can be constructed
through above-described wire arrangement of six axial wires, which
is shown in FIG. 8.
[0087] FIG. 9 shows a three-dimensional Kagome truss aggregate,
which is constructed with wires in the above-described manner. It
shows a three-dimensional truss-type cellular light structure 11,
in which the unit cell of FIG. 7 or FIG. 8 is repeatedly
combined.
[0088] As shown in FIG. 10, the three-dimensional cellular light
structure 11 of the Kagome truss type appears differently depending
on the viewing direction. Particularly, the figure at the bottom of
FIG. 10, as viewed from one of the six-dimensional wire groups, is
substantially similar to the two-dimensional Kagome truss of FIG.
6. That is, the three-dimensional cellular light structure 11 is
appeared as the same shape and pattern when seen along the axial
direction of six wires, which are intercrossed with each other at
the same angle (60 degrees or 120 degrees).
[0089] Each intersection point, at which three wires are
intercrossed, corresponds to a vertex of the regular tetrahedron.
As shown in FIG. 11, the wires are intercrossed in two difference
modes when seen from the right front of the vertex. As illustrated
respectively in the upper and lower figures of FIG. 11, the three
wires may be intercrossed in such a manner to be overlapped
clockwise or counterclockwise. In the case where the wires are
intercrossed in a clockwise-overlapped pattern, the regular
tetrahedron constituting a unit cell has a concave form as shown in
the upper illustration of FIG. 12. If the wires are intercrossed in
a counterclockwise-overlapped pattern, the regular tetrahedron
constituting a unit cell has a convex form. Nevertheless, both
cases may result in a cellular light structure, which is intended
in the present invention and has a similar structure to the ideal
Kagome truss or the Octet truss as described below. Now, a method
for manufacturing the three-dimensional cellular light structure
will be described.
[0090] FIG. 41 is a flowchart showing the manufacturing procedures
of the three-dimensional truss-type cellular light structure formed
of the wires according to the earlier-filed invention. According to
the manufacturing method, a basic equilateral triangle is formed by
intercrossing three wires 4, 5, and 6 in an X-Y plane. Then, a
basic regular tetrahedron (a first regular tetrahedron) is
constructed in such a manner that a wire 7 intercrosses the
intersection point of the wires 5 and 6, a wire 8 intercrosses the
intersection point of the wires 4 and 5, a wire 9 intercrossed the
intersection point of the wire 6 and 4, the three wires 6, 9, and 7
are intercrossed so as to form an equilateral triangle, the three
wires 4, 8, and 9 are intercrossed so as to form an equilateral
triangle, and the three wires 5, 7, and 8 are intercrossed so as to
form an equilateral triangle. Next, above the vertex of the first
regular tetrahedron formed by the wires 4 to 9, another basic
equilateral triangle is formed by intercrossing three wires 4', 5',
and 6', each of which has the same orientation as the wire 4, 5,
and 6 respectively. Thereafter, another regular tetrahedron (a
second regular tetrahedron) is constructed in such a manner that
the three wires 4', 8, and 9, the three wires 5', 7, and 8, and the
three wires 6', 9, and 7 respectively are intercrossed so as to
form an equilateral triangle. Accordingly, at both sides of the
intersection point (vertex) formed by the three wires 7, 8, and 9,
the first regular tetrahedron (formed by the wires 4, 5, 6, 7, 8,
and 9) and the second regular tetrahedron (formed by the wires 4',
5', 6', 7, 8, and 9 are constructed to face each other and form a
unit cell. In the same way as above, the wires are disposed such
that an opposing tetrahedron can be formed at other vertexes of the
first regular tetrahedron formed by the six wires 4 to 9, and thus
a plurality of unit cells can be repeatedly formed to thereby
fabricate a three-dimensional cellular light structure. In this
case, the first and second regular tetrahedrons have a similar
shape. In the case where the similarity ratio thereof is 1:1, they
form a structure similar to the Kagome truss. If the similarity
ratio is much higher than 1:1, they come to make a structure
similar to the Octet truss as described above.
[0091] An embodiment of the present invention will be hereafter
described in detail with reference to FIGS. 13 through 39 and
42.
[0092] FIG. 13 is a picture of a helical wire; FIG. 14 is a picture
of a plurality of wires twisted together by a twisting machine; and
FIG. 15 is a picture of the twisting machine for forming the
helical wire.
[0093] FIG. 16 is a picture of helical wires for the 1st, 2nd, 3rd,
4th, 5th, and 6th-axes; FIG. 17 is a picture of a frame assembly
for assembling the helical wires; FIG. 18 is a picture showing the
1st, 2nd and 3rd-axis wires assembled on a frame of the frame
assembly to form the two-dimensional Kagome plane; FIG. 19 is a
picture showing two layers of the two-dimensional Kagome planes
assembled on frames of the frame assembly; FIG. 20 is a picture
showing the 4th, 5th and 6th-axis wires assembled with the
two-dimensional Kagome planes; FIG. 21 is a picture of a completed
three-dimensional cellular light structure with the frames
removed.
[0094] FIG. 22 is a plane view of the 1st and 2nd-axis wires, where
the 1st-axis wires are first disposed and then the 2nd-axis wires
are disposed to overlap; FIG. 23 is a plane view showing the step
of assembling the 3rd-axis wires; FIG. 24 is a plane view of a
single layer of the two-dimensional Kagome plane formed of the 1st,
2nd and 3rd-axis wires; FIGS. 25 and 26 are a plane view and a
picture showing the single layer of the two-dimensional Kagome
plane assembled to the frame; FIG. 27 is a plane view showing a
method of laminating the two-dimensional Kagome planes of A, B, C
layers; FIGS. 28 and 29 are a perspective view and a picture
showing two layers of the two-dimensional Kagome plane with the
frames; FIG. 30 is a perspective view of two layers of the
two-dimensional Kagome plane with the frames removed; FIG. 31 is a
perspective view of three layers of the two-dimensional Kagome
plane with the frames; FIG. 32 is a perspective view of three
layers of the two-dimensional Kagome plane with the frame removed;
FIG. 33 is a plane view and a side view showing the step of
assembling the 4th-axis wires with the 1st, 2nd and 3rd-axis wires
in the two-dimensional Kagome planes; FIG. 34 is a plane view and a
side view showing the step of assembling the 5th-axis wires with
the 1st, 2nd, and 3rd-axis wires in the two-dimensional Kagome
plane; FIG. 35 is a plane view and a side view showing the step of
assembling the 6th-axis wires with the 1st, 2nd, and 3rd-axis wires
in the two-dimensional Kagome plane; FIG. 36 is a perspective view
showing the step of assembling the last wire of the six axes wires;
FIG. 37 is a perspective view showing the step of assembling the
last wire of the six axes wires, when seen from a moving direction
of the last wire; FIGS. 38 to 40 are a perspective view or a
picture of the final structure after the 1st, 2nd, 3rd, 4th, 5th
and 6th-axis wires are completely assembled.
[0095] FIG. 42 is a flowchart outlining processes for manufacturing
a three-dimensional cellular light structure according to another
embodiment of the present invention.
[0096] A three-dimensional cellular light structure according to
another embodiment of the present invention is constructed by wires
1, 2, 3, 4, 5, 6, 4', 5', 6', 7, 8 and 9 formed in a helical shape
as shown in FIG. 13. That is, the six-axial wire groups for
constructing the ideal Kagome truss or Kagome-like
three-dimensional light structure according to the present
invention are pre-fabricated in a helical shape. The amplitude and
the pitch of the helical wires need to be determined so that the
truss structure can be easily fabricated and three wires in
different orientation can closely contact at each intersection
point, thereby ensuring stability of the truss structure. For
example, when the amplitude of the helical wire is too large, the
truss structure can be easily fabricated but the overall truss
structure may be loose because the wires do not closely contact at
the intersection points. In this respect, it is preferred that the
pitch of the helical wires is two times the length of the side of
the regular tetrahedron constituting the unit cell of the truss
structure.
[0097] The helical wires are formed by twisting a plurality of
wires as shown in FIG. 14 using the twisting machine of FIG. 15.
The pitch (P) of the helical wire can be adjusted according to the
specification of the three-dimensional cellular light structure to
be fabricated.
[0098] Yet, this method for forming the helical wires comprises a
step of installing jigs at both sides of the twisting machine, a
step of securely fixing both ends of two to four wires to the jigs,
and a step of twisting the wires by the operation of the machine.
According to this method, although the wires can be easily
fabricated, its mechanism is too complicated and discontinuous to
be applied to a machine for manufacturing a bulk Kagome.
[0099] Selectively, besides this method, a helical wire bending
machine may be used or the helical wires may be formed by winding a
wire around a rod having helical grooves. However, these methods
have advantages and disadvantages, respectively. It is necessary to
further develop an apparatus having a simplified structure, easy to
operate, and suitable for continuous processes.
[0100] After the helical wires are prepared as shown in FIG. 16,
the wires are used to form the two-dimensional Kagome planes. At
this time, a frame assembly 20 comprising a rectangular frame 21
and connection support rods 22 is used, as shown in FIG. 17.
[0101] The 1st-axis wires 4 and the 2nd-axis wires 5 are disposed,
and then the 3rd-axis wires 6 are rotated and inserted between the
1st-axis wires 4 and the 2nd-axis wires 5. For this step to be
carried out, the 1st-axis wires 4 and the 2nd-axis wires 5 should
be securely fixed, and thus the frame 21 plays an important
role.
[0102] In addition, after the two-dimensional Kagome planes are
formed, the 4th-axis wires 7 are inserted across the
two-dimensional Kagome planes, and then 5th-axis and 6th-axis wires
8 and 9 are inserted while being rotated across the two-dimensional
Kagome planes. Therefore, the frame is necessary to securely fix
the two-dimensional Kagome planes.
[0103] FIG. 18 shows a two-dimensional Kagome plane fabricated by
arranging the 1st-axis wires 4 and the 2nd-axis wires 5 on a frame
21 and inserting a 3-axis wire 6 while rotating the same.
[0104] FIG. 19 shows two layers of the two-dimensional Kagome
planes assembled on frames of the frame assembly.
[0105] FIG. 20 shows the 4th, 5th and 6th-axis wires 7, 8 and 9
inserted across the two-dimensional Kagome planes.
[0106] FIG. 21 shows a completed three-dimensional cellular light
structure with the frames removed.
[0107] Hereafter, the manufacturing procedures of the
three-dimensional cellular light structure formed of the helical
wires woven by means of the frame assembly 20 are described in more
detail.
[0108] First, as shown in FIG. 22, the 1st-axis wires 4 are
disposed, and then the 2nd-axis wires 5 are disposed so as to form
rhombuses.
[0109] Next, as shown in FIG. 23, the 3rd-axis wires 6 are rotated
and inserted between the 1-axis wires 4 and the 2-axis wires 5, so
as to form a single layer of the two-dimensional Kagome plane.
[0110] FIG. 24 shows the single layer formed by the 1st-axis wires
4, the 2nd-axis wires 5 and the 3rd-axis wires 6.
[0111] While the frame assembly 20 is not shown in FIGS. 22 and 23
for simplicity of the drawings, the single layer is formed in the
frame assembly 20 as shown in FIGS. 25 and 26.
[0112] FIG. 27 shows the arrangement of the wires in three
successive layers of the two-dimensional Kagome planes, and each
layer is designated as layer A, layer B and layer C. The wires in
the layers A to C are arranged so that the position deviations of
the wires in horizontal and vertical direction between two
neighboring layers are l.sub.x and l.sub.y, respectively. The
frames 21 of the layers A to C may be rectangular or, if necessary,
have other shapes.
[0113] Herein, lx=P/2, ly={square root over (3)}P/6, P=wire
pitch.
[0114] After the 1st, 2nd and 3rd-axis wires 4, 5 and 6 are
arranged on the frame 21 of the frame assembly 20 as
above-mentioned, the layers are disposed so that the height
difference between two layers are constant (H={square root over
(3)}P/3, P=wire pitch), thereby forming the structure as shown in
FIGS. 28 and 29.
[0115] FIGS. 31 and 32 show three layers disposed at a constant
height difference (H={square root over (3)}P/3).
[0116] As above, after the 1st, 2nd and 3rd-axis wires 4, 5 and 6
are disposed, the 4th-axis wires 7 are assembled as shown in the
front view and the side view of FIG. 33, the 5th-axis wires 8 are
assembled among the 1st, 2nd, 3rd and 4th-axis wires 4, 5, 6 and 7
as shown in the front view and the side view of FIG. 34. Then, the
6th-axis wires 9 are rotated and inserted among the 1, 2, 3, 4 and
5-axis wires 4, 5, 6, 7 and 8 as shown in the front view and the
side view of FIG. 35.
[0117] FIG. 36 is a perspective view showing the step of assembling
the last wire of the six axes wires, and FIG. 37 is a perspective
view showing the step of assembling the last wire, when seen from a
moving direction of the last wire;
[0118] FIGS. 38 and 39 show the final structure after the 1st, 2nd,
3rd, 4th, 5th and 6th-axis wires are completely assembled;
[0119] A method for manufacturing a three-dimensional cellular
light structure according to another embodiment of the present
invention comprises a helical wire forming step of forming 1st,
2nd, 3rd, 4th, 5th and 6th-axis helical wires 4, 5, 6, 7, 8 and 9;
a two-dimensional Kagome plane forming step of forming a plurality
of two-dimensional Kagome planes by assembling the 1st, 2nd and
3rd-axis helical wires 4, 5 and 6 on frames 21 of a frame assembly
20; a frame laminating step of connecting and laminating the frames
21 by means of connection support rods 22; and a step of forming a
three-dimensional cellular light structure by connecting the 4th,
5th and 6th-axis helical wires 7, 8 and 9 to the 1st, 2nd and
3rd-axis helical wires 4, 5 and 6 in each frame 21.
[0120] The wire material of the three-dimensional truss-type
cellular light structure is not specifically limited, but may
employ metals, ceramics, fibers, synthetic resins, fiber-reinforced
composite, or the like.
[0121] In addition, the intersection points among the above wires
4, 5, 6, 4', 5', 6', 7, 8 and 9 may be firmly bonded. In this case,
the bonding means is not specifically limited, but may employ a
liquid or spray adhesive, brazing, soldering, welding, and the
like.
[0122] Furthermore, there is no limitation in the diameter of the
wires and the size of the cellular light structure. For example,
iron rods of tens of millimeters in diameter can be employed in
order to construct a structural material for buildings, etc.
[0123] On the other hand, if wires of a few millimeters are use,
the resultant cellular light structure can be used as a frame
structure for fiber reinforced composite material. For example,
using the three-dimensional cellular light structure of the
invention as a basic frame, a liquid or semi-solid resin or metal
may be filled into the empty space of the structure and then
solidified to thereby manufacture a fiber reinforced composite
material having a good rigidity and toughness. Furthermore, in the
case where the three-dimensional cellular light structure of Octet
type as shown in FIG. 12 is used, the smaller one of the two
tetrahedrons constituting the unit cell may be filled with resin or
metal to manufacture a fiber reinforced composite material. This
fiber reinforced composite material is isotropic or almost
isotropic and thus has uniform material properties regardless of
its orientation. Therefore, it can be cut into any arbitrary
shapes. Also, the wires are interlocked in all directions, thereby
preventing damages such as delamination or pull-out of wires, which
can occur in the conventional composite materials.
[0124] Although a few embodiments of the present general inventive
concept have been shown and described, it will be appreciated by
those skilled in the art that changes may be made in these
embodiments without departing from the principles and spirit of the
general inventive concept, the scope of which is defined in the
appended claims and their equivalents.
* * * * *