U.S. patent number 3,831,503 [Application Number 05/360,335] was granted by the patent office on 1974-08-27 for method of making cell structure.
Invention is credited to George V. Tranquillitsky.
United States Patent |
3,831,503 |
Tranquillitsky |
August 27, 1974 |
METHOD OF MAKING CELL STRUCTURE
Abstract
A cell structure and method of fabricating the same. Cell
structures embodying the invention may be used to fabricate panels,
beams, and like components having utility in a great number of
environments such as in the construction of side, floor and ceiling
walls of a building and of material-handling pallets. Any such
panel or beam structure comprises a plurality of sub-components or
segments each constituted of a number of cells, with all of the
segments forming any such panel or beam being connected one with
another so as to define a panel or beam having the desired
dimensions. Each such segment includes a plurality of cells in the
form of substantially closed polyhedrons hingedly connected one
with another in a string-like succession thereof; and each such
string of polyhedrons is fabricated by scoring a continuous web of
flat paper or paper-like material which is then folded along the
score lines into a continuous string of interconnected polyhedrons.
The folded web is then adhesively or otherwise constrained in the
folded condition thereof to maintain the string-like succession of
interconnected polyhedrons.
Inventors: |
Tranquillitsky; George V.
(Oakland, CA) |
Family
ID: |
26783907 |
Appl.
No.: |
05/360,335 |
Filed: |
May 14, 1973 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
91384 |
Nov 20, 1970 |
|
|
|
|
Current U.S.
Class: |
493/399;
428/542.2; 446/488; 52/793.1 |
Current CPC
Class: |
B65D
19/0002 (20130101); E04C 2/40 (20130101); E04C
3/28 (20130101); B65D 19/38 (20130101); B65D
2519/00323 (20130101); B65D 2519/00019 (20130101); B65D
2519/00358 (20130101); B65D 2519/00562 (20130101); B65D
2519/00343 (20130101); B65D 2519/00273 (20130101); B65D
2519/00288 (20130101); B65D 2519/00054 (20130101) |
Current International
Class: |
B31B
3/00 (20060101); E04C 2/40 (20060101); E04C
3/28 (20060101); E04C 3/02 (20060101); B65D
19/38 (20060101); B31d 005/04 () |
Field of
Search: |
;93/1R,1F,1H,1WZ,84R
;52/615,618,630 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lake; Roy
Assistant Examiner: Coan; James F.
Attorney, Agent or Firm: Gardner; Joseph B.
Parent Case Text
This is a division, of application Ser. No. 91,384, filed Nov. 20,
1970.
Claims
What is claimed is:
1. In a method of fabricating a lightweight structural component,
the steps of: providing a long, continuous, generally
two-dimensional web of material having longitudinal edges and a
longitudinal axis intermediate the same; folding said web along
said axis and along lines defining therewith and with said
longitudinal edges a plurality of polygons connected one to another
into a continuous string of interconnected tetrahedronal cells
disposed one after another in an essentially continuous succession
thereof each of which is a substantially closed figure having at
least one edge formed by the adjacency of non-contiguous surface
portions of said web; and constraining said web in the folded
condition thereof to maintain said string of interconnected cells,
the folding of said web including a twisting thereof along said
axis whereby the longitudinal edges of said web follow a generally
helical path along the length of said string of cells.
2. The method of claim 1 including the further steps of disposing a
plurality of strings in side-by-side juxtaposition with the cells
defined by one string nesting within the spaces provided between
successive cells of the juxtaposed strings.
3. The method of claim 1 in which the step of folding said web
includes folding the same along intersecting lines such that said
polygons are triangles each having two angles respectively
approximating 55.degree., said tetrahedronal cells having faces of
triangular configurations.
4. The method of claim 3 in which the folding of said web
progresses longitudinally along the length thereof and is continued
in one predominant direction such that the successive tetrahedronal
cells in each string thereof are interconnected along the fold line
extending between the 55.degree. angles of the triangular faces
contiguous with such fold line.
5. The method of claim 3 in which the folding of said web
progresses longitudinally along the length thereof and is continued
in one predominant direction such that the successive tetrahedronal
cells in each string thereof are interconnected along the fold line
extending between one of said 55.degree. angles and the third angle
of the triangular faces contiguous with such fold line.
6. The method of claim 3 in which the step of providing said web
includes the provision of a substantially planar, relatively stiff,
bendable web; and including the further step of scoring said web
along said longitudinal axis and fold line prior to folding the
web.
7. The method of claim 6 including the further step of disposing a
plurality of strings in side-by-side juxtaposition with the cells
defined by one string nesting within the spaces provided between
successive cells of the juxtaposed strings.
8. The method of claim 3 in which a plurality of said strings of
cells are provided; and including the further step of helically
winding said strings one into intertwined nesting relation with
another to provide a composite structure.
9. In a method of fabricating a lightweight structural component,
the steps of: providing a long continuous, substantially planar,
relatively stiff, bendable web of material and scoring the same to
form fold lines defining a plurality of polygons connected one to
another along said fold lines; folding the scored web along said
fold lines into a continuous string of interconnected polyhedronal
cells each of which is a substantially closed figure having at
least one edge formed by the adjacency of non-contiguous surface
portions of said web; and constraining said web in the folded
condition thereof to maintain said string of interconnected cells;
said web being substantially wider than the cell-forming portion
thereof to provide an integral overwrap section, the step of
scoring said web including scoring the overwrap section thereof to
define a longitudinal succession of parallelograms therealong, and
the step of folding the scored web including overwrapping said
continuous string of polyhedronal cells with said integral overwrap
section to form an essentially self-sustaining structural
segment.
10. In a method of fabricating a lightweight structural component,
the steps of: providing a long, continuous, substantially planar,
relatively stiff, bendable web of material; folding said web along
lines defining a plurality of polygons connected one to another
along such lines into a continuous string of interconnected
polyhedronal cells each of which is a substantially closed figure
having at least one edge formed by the adjacency of non-contiguous
surface portions of said web; and constraining said web in the
folded condition thereof to maintain said string of interconnected
cells; said web being substantially wider than the cell-forming
portion thereof to provide an integral overwrap section, and the
step of folding said web including overwrapping said continuous
string of polyhedronal cells with said integral overwrap section to
form an essentially selfsustaining structural segment.
11. The method of claim 10 in which the step of overwrapping said
string of cells with said overwrap section includes folding the
latter along lines defining a longitudinal succession of
parallelograms therealong.
Description
DISCLOSURE
This invention relates to cell structures and to a method of
fabricating the same, and it relates more particularly to
lightweight and inexpensive panels, beams, and similar structural
components comprised of such cell structures, and to a method of
fabricating such components therefrom. Structural components
embodying the invention may be made in a variety of sizes both
large and small, and they have utility in a great many environments
as, for example, in the construction of building walls and
material-handling pallets.
An object of the invention is to provide novel and improved
structural components such as panels, beams, and the like having
superior strength-to-weight ratios but which components are
nevertheless inexpensive, being fabricated from readily available
materials that are themselves of low cost.
Another object of the invention is in the provision of a novel and
improved method of fabricating cells, string-like segments
comprising an interconnected succession thereof, and structural
components formed thereof all in a continuous-type process which
significantly reduces the cost of construction by affording high
speed, volume production using automatic and semi-automatic
machinery.
Still another object is that of providing a panel structure, beam,
or like structural component and a method of making the same, as
heretofore described, in which a long continuous web of planar
material is scored to form fold lines thereon and is thereafter
folded along such lines into a continuous string of interconnected
cell-like polyhedrons each of which is a substantially closed
figure, and in which the folded web is then secured in the folded
condition thereof to maintain the structural integrity of the
string of interconnected polyhedrons.
A further object is to provide an improved structural component and
method of fabricating the same in which the continuous individual
segments, each comprising a succession of interconnected cells, are
cut into proper lengths and then assembled one with another to form
a component having any desired dimensional extent.
Yet a further object is in the provision of an improved cell and
structural component comprised thereof and to a method of
fabricating the same, all of the character heretofore described, in
which the continuous webs of material may be paper or the like
(ordinary Kraft paper or paperboard, for example), sufficiently
stiff to maintain the configurations into which they are
folded.
Still a further object is that of providing a structural
composition of the type indicated in which the interconnected
polyhedrons are tetrahedrons having planar faces each of which is
triangular, wherefore the strength of the web material used in the
construction of the continuous strings of polyhedrons is enhanced
and augmented by the intersecting edges of the polyhedrons defined
by the interconnected faces thereof.
Additional objects and advantages of the invention, especially as
concerns particular features and characteristics thereof, will
become apparent as the specification continues.
Embodiments of the invention are illustrated in the accompany
drawings, in which:
FIG. 1 is a broken perspective view of a panel embodying the
invention;
FIG. 2 is a broken top plan view of a flat blank or web from which
a continuous string of interconnected polyhedronal cells is formed,
the web being scored to provide fold lines therealong;
FIG. 3 is a broken perspective view illustrating the web shown in
FIG. 2 being folded in a first direction to form a string of
interconnected polyhedrons;
FIG. 3 is essentially a top plan view, partly in section, of one of
the polyhedrons comprising the string thereof illustrated in FIG.
3;
FIG. 5 is a broken perspective view illustrating the web shown in
FIG. 2 being folded in a second direction to form a slightly
different string of interconnected polyhedrons;
FIG. 6 is essentially a top plan view, partly in section, of one of
the polyhedrons comprising the string thereof illustrated in FIG.
5;
FIG. 7 is a broken top plan view showing two strings of polyhedrons
of the type illustrated in FIG. 5 being joined in side-by-side
relation in the formation of a beam or panel;
FIG. 8 is for the most part a broken side view in elevation taken
generally along the line 8--8 of FIG. 7 but with portions of the
structure broken away to illustrate internal characteristics;
FIG. 9 is a broken top plan view, somewhat similar to that of FIG.
7, illustrating two of the strings shown in FIG. 3 and one of the
strings shown in FIG. 5 being wound together to form a beam or
panel;
FIG. 10 is a broken top plan view of a modified web or blank
diagrammatically illustrating the step of scoring the same;
FIG. 11 is a broken perspective view showing a scored blank of the
type illustrated in FIG. 10 being folded to form a structural
segment comprising a string of tetrahedrons defined in part by and
enclosed within planar side walls; and
FIG. 12 is a broken perspective view of a beam comprising a
plurality of segments of the type shown in FIG. 11.
Prior to a detailed description of the embodiments of the invention
shown in the drawing, it may be observed that panels, beams, and
other structural components embodying the invention are strong,
lightweight members having utility in many environments as, for
example, in residential, commercial and industrial buildings in
which the components may be horizontally or vertically disposed and
form side, floor and ceiling walls or elements thereof. One
exemplary structural component in the form of a panel is shown in
FIG. 1, and it is designated in its entirety with the numeral 15.
The building panel illustrated includes an inner core 16 comprised
of a plurality of panel segments 17 disposed in side-by-side
juxtaposition and secured one to another by any suitable means,
such as adhesively. In the panel being considered, the core 16 is
sandwiched between outer laminations or surface elements 18 which
may be adhesively or otherwise secured to the core. As respects the
present invention, the laminations or facings 18 may be of any
suitable type -- rigid, flexible or otherwise -- and may be plain
or decorated for esthetic purposes, all of which will depend upon
the particular use and environment intended for the panel.
The panel segments 17 each include one or more substantially
continuous strings of polyhedrons each of which is an essentially
closed geometric figure having generally planar faces, and such
polyhedrons and the string-like succession thereof are formed from
substantially planar webs or blanks which are long and may be
withdrawn from large supply rolls for processing in a continuous
fabrication operation. A portion of such a web is illustrated in
FIG. 2 and is denoted with the numeral 19. The web 19 is
constituted of a substantially planar, relatively stiff, bendable
material which may take a variety of forms with a particular
instance thereof being a relatively tough paper such as heavy Kraft
paper or paperboard which may or may not be impregnated or
otherwise treated with various substances (a resin plastic, for
example) to strengthen the material, provide waterproofing
therefor, or otherwise contribute particular characteristics
thereto.
The continuous web 19 has substantially parallel longitudinal edges
20 and 21, and it is scored to provide fold lines that define a
plurality of polygons 22 on the web which are connected one to
another along the fold lines. The polygons 22 are all substantially
identical triangles, and the intersecting fold lines defining the
same are arranged into a first group constituting a plurality of
substantially parallel, longitudinally or axially spaced lines 23
that are angularly disposed so as to incline downwardly and toward
the left, as viewed in FIG. 2, and into a second group constituting
a plurality of substantially parallel, longitudinally or axially
spaced lines 24 which are angularly disposed so as to incline
downwardly and toward the right as viewed in FIG. 2. The lines 23
and 24 intersect each other along a center line 25 which is
essentially parallel to the longitudinal edges 20 and 21.
Accordingly, a plurality of four triangular polygons 22 are defined
between any two successive lines 23 or between any two successive
lines 24.
The lines 23 and 24 also intersect along the longitudinal edges 20
and 21 of the web 19 and are disposed with respect to such edges so
that each line 23 intersecting the same forms one 55.degree. angle
therewith, and each line 24 intersecting such edges forms one
70.degree. angle therewith. Accordingly, the included angle defined
by any two intersecting lines 23 and 24 is substantially
55.degree., and it is evident then that each triangular polygon 22
has two 55.degree. angles and one 70.degree. angle. For purposes of
identification, the 55.degree. angles in each triangle are denoted
with the Letter S and each 70.degree. angle thereof is denoted with
the Letter L. As will become apparent hereinafter, the scored web
19 is folded to form a string of interconnected polyhedrons, and it
may be folded so that the successive polyhedrons are interconnected
one with another either along an axis or fold line extending
between two 55.degree. angles or a fold line extending between one
55.degree. and the 70.degree. angle.
FIG. 3 depicts a scored web 19 being folded in one particular
direction to form a substantially continuous string of
interconnected polyhedrons 26 each of which is an essentially
closed figure having at least one edge portion formed by the
junction of non-contiguous surface portions of the web 19 or,
specifically, by the junction of the longitudinal edges 20 and 21
thereof. The polyhedrons 26 are interconnected one with another
along fold lines extending between one of the 55.degree. angles S
and a 70.degree. angle L and, as shown most clearly in FIG. 4, each
polyhedron 26 is a tetrahedron in which the four sides thereof are
respectively defined by the aforementioned substantially planar
polygons 22. The web 19 after being folded to form the string of
successive polyhedrons 26 is constrained in its folded condition in
any suitable manner as, for example, by adhesively securing the
edge portions 20 and 21 to each other by any conventional means
such as adhesives, overlying tape, an overlapping flap joint,
etc.
The string of polyhedrons 26 is formed in a continuous process in
which a flat web 19 is first scored to provide the fold lines 23,
24, and 25, and is then folded in one predominant angular,
direction relative to the longitudinal axis of the web (as shown in
FIG. 3) so as to form closed polyhedrons which are joined one to
another along a common fold line extending between one 55.degree.
angle S and the 70.degree. angle L of the triangular faces adjacent
such fold line.
FIG. 5 depicts a scored web 19 being folded in a second particular
direction (opposite to the direction of the fold depicted in FIG.
3) to form a substantially continuous string of interconnected
polyhedrons 26' each of which is a substantially closed figure
having at least one edge portion formed by the junction of
non-contiguous surface portions of the web 19 or, specifically, by
junction of the longitudinal edges 20 and 21 thereof. The
polyhedrons 26' are interconnected one with another along fold
lines extending between the two 55.degree. angles S and, as shown
most clearly in FIG. 6, each polyhedrons 26' is a tetrahedron in
which the four sides thereof are respectively defined by the
aforementioned substantially planar polygons 22. The web 19 after
being folded to form the string of successive polyhedrons 26' is
constrained in its folded condition, as in the case of the string
forming the polyhedrons 26. The string of polyhedrons 26' is
constructed in a continuous process, as heretofore described with
respect to the string forming the polyhedrons 26.
In fabrication of a panel 15 or core 16 thereof, a plurality of
strings of polyhedrons are assembled and the particular manner of
assembly and structural composition of the core may vary
considerably and, at least to some extent, will depend upon the
particular characteristics of the strings being used. FIGS. 7 and 8
illustrate typical assemblages of a plurality of string-like
successions of polyhedrons, and in FIG. 7 two substantially
identical strings each comprising a succession of polyhedrons 26'
(as shown in FIG. 5) are disposed in side-by-side juxtaposition
with the polyhedrons defined by one string nesting within the
spaces provided between successive polyhedrons of the juxtaposed
strings. As a result of such nesting of the polyhedrons of one
string within the spaces defined between polyhedrons of the
adjacent strings, the opposite faces of the assemblage are
essentially planar and substantially parallel to each other.
In this reference, it may be observed that in order to effect such
planar faces, the polyhedrons 26' which are hingedly connected to
each other along horizontal fold lines are displaced toward each
other (downwardly and inwardly with respect to one pair, and
upwardly and inwardly with respect to the next successive pair, as
viewed in FIG. 8) so that the top and bottom faces 22T and 22B are
in planar juxtaposition. It will be appreciated that the contiguous
faces of the polyhedrons 26' in any one string thereof and the
contiguous faces of adjacent strings of polyhedrons may be secured
to each other in any appropriate manner, as by means of
adhesives.
Another technique for constructing panel segments is shown in FIG.
9, and it constitutes the interconnection of an intertwined
configuration of mixed strings of polyhedrons 26 and 26',
respectively shown in FIGS. 3 and 5. In the particular embodiment
shown in FIG. 9, the panel segment is constructed of two strings of
polyhedrons 26 and one string of polyhedrons 26', and the strings
comprising the polyhedrons 26 are wound about the outer string
comprised of the polyhedrons 26'. In this construction, the strings
of polyhedrons 26 are each wound in a clockwise rotation about the
string of polyhedrons 26', which tends to maintain the
configuration shown in FIG. 5 in which the fold lines
interconnecting successive polyhedrons are alternately disposed in
horizontal and vertical orientations located in common horizontal
and vertical planes intersecting each other along the center line
of the string. As in the case of the segment formed by the strings
of polyhedrons 26' shown in FIG. 7, the opposite top and bottom
faces of the panel segment are essentially planar and substantially
parallel, thereby forming a segment that is generally rectangular
in cross section. It may be noted that a panel segment can be
formed by winding two strings of polyhedrons 26, omitting the
string of polyhedrons 26'.
FIGS. 10 and 11 are concerned with a modified construction used in
forming the core 16 and segments thereof illustrated in FIG. 1. The
segments 17 are all rectangular in cross section (square-shaped in
the particular embodiment be considered), and are fabricated in a
single continuous operation involving only one blank or web. Such a
web is illustrated in FIG. 10, and referring thereto, the web
(which is denoted in its entirety with the numeral 27) is an
elongated continuous component, generally rectangular in plan view,
and it is composed of two parallel rectangular sections integral
with each other and bounded at their outer extremities by parallel
longitudinal edges 28 and 29. The web 27 is cored to provide fold
lines therealong, and one such line (denoted with the numeral 30)
is oriented at the center of the web to divide the same into the
aforementioned sections, and such line is substantially parallel to
the longitudinal edges 28 and 29.
As in the case of the web 19, the portion of the web 27 defined
between the parallel lines 28 and 30 is divided into a plurality of
polygons 32 which are all substantially identical triangles and are
formed by a plurality of intersecting lines 33 and 34 which cross
each other along a center line 35 intermediate the longitudinally
extending edges 28 and 30 and substantially parallel thereto. The
fold lines 33, 34, and 35 are related to each other and to the
longitudinal edges 28 and 30 in precisely the same manner as the
arrangement heretofore described with respect to the web 19, and
because of this identity, need not be further described.
The web section defined between the edges 29 and 30 is divided into
parallelograms 36 by angularly disposed, essentially parallel lines
37 which form continuations of the lines 34 but have a somewhat
greater angular disposition with respect to the edges 29 and 30
intersected thereby. The web 27 is scored and folded in a
continuous operation and, as shown in FIG. 11, such folding of the
web constructs a plurality of polyhedrons 38 which are hingedly
interconnected to each other to form a string-like succession
thereof in the manner of the polyhedrons 26 and 26', all as
described hereinbefore. The polyhedrons 38 are closed geometric
figures having four sides so as to define tetrahedrons having
substantially planar faces each of which is triangular. Certain of
the polyhedrons 38 are closed on one side by the parallelograms 36
which constitute an overwrapping for the string of polyhedrons and
establish four planar faces arranged in opposite parallel pairs, as
is most evident in FIG. 11. The overwrap formed by the
parallelograms 36, which are hingedly connected to each other as
well as to the polyhedrons along the fold line 30, may be fixed or
held in position by adhesive or any other comparable means.
The segments 17 formed from the planar web 27 are essentially
complete, self-sustaining integers that are very firm and rigid,
whereas the strings of polyhedrons 26 and 26' formed from the webs
19 are flexible, bendable components with each polyhedron being
angularly displaceable relative to those connected thereto along
the respectively associated hinge lines therebetween. Accordingly,
each of the polyhedron strings 26 and 26' respectively shown in
FIGS. 3 and 5 requires integration with other strings (as shown in
FIGS. 7 and 8) in order to provide self-sustaining rigidity.
It will be appreciated from the foregoing description that strong,
lightweight panels 15 are formed simply and economically in
substantially continuous processes in which flat webs are advanced
through a succession of stages one of which is a scoring station at
which the flat web is scored so as to define fold lines therealong,
and the next station of which is the folding station at which the
scored web is folded into a string of polyhedrons connected one to
another in a continuous succession thereof. The folded webs are
secured in their folded condition to maintain the string of
interconnected polyhedrons; and in the case of the web 27 and panel
segments 17 formed thereby, a complete structural element is
constructed which needs no further attention except to be divided
into appropriate lengths. In the case of the polyhedrons comprising
the strings 26 and 26', they are assembled with like strings, as
shown in FIGS. 7 and 9, so as to form self-sustaining panel
components. In either case, after appropriate lengths are assembled
to form a panel, the assemblage may be covered on one or both sides
thereof with outer laminations 18, if this is desired.
It will be apparent that the polyhedrons and strings defined
thereby can be reinforced or strengthened in any desired manner as,
for example, by impregnating the same, and in certain instances the
material used to join adjacent strings and panel segments may
contribute to the strength of the panel or, in certain cases, may
provide all or most of the structural strength thereof with the
adjacent faces of the strings even being spaced apart to define a
mold form for an initially flowable material which hardens to
furnish the requisite structural strength. In any event, the
angular dispositions of the interrelated polyhedrons provide
considerable strength much in excess of that which would be
expected from the material from which the webs 19 and 28 are
formed. Also, the polyhedrons afford excellent thermal insulation
because each closed polyhedron defines a dead-air space therewithin
which provides considerable inhibition to heat migration
therethrough. It will be appreciated, however, that the hollow
polyhedrons can be filled with a thermal insulating material (or
other material having special features) which would further enhance
the insulating characteristics of the panel 15.
From the foregoing description, it will be appreciated that the
elemental member in the structural composition is a hollow cell of
polyhedronal configuration which, in more particular terms, is a
tetrahedron having triangular faces which usually have two included
angles of 55.degree. and a third angle of 70.degree.. Such specific
angles are not required for the form of the invention illustrated
in FIG. 11 in which the succession of polyhedrons is enclosed in an
overwrap. The faces of each cell are integral, being formed from a
unitary web, and the cells are hingedly interconnected one to
another to form a structural segment as, for example, the three
divergent segments respectively illustrated in FIGS. 3, 5, and 11.
A plurality of individual segments are then joined one with another
to fabricate a structural component which may be a beam, panel, or
be of any other type.
Structural segments of the type shown in FIG. 11 are
self-sustaining and may be used directly as a beam or column. As
explained heretofore, such segments may be joined one to another in
side-by-side juxtaposition, as shown in FIG. 1, to form a
single-layer panel. However, such segments may be joined one to
another in multiple layers to form a beam (or column) 39, as
illustrated in FIG. 12. Any desired number of such beam-like
segments may be united to define a beam having any desired
dimensions and, accordingly, any desired strength.
Not only do structural components embodying the invention have an
excellent strength-to-weight ratio, but segments comprising a
string of interconnected cells have generally equal strength in all
directions because of the multidirectional fold lines
interconnecting the various faces of any one polyhedronal cell and
interconnecting successive cells in the previously described
string-like disposition thereof. Accordingly, any structural
component comprising a plurality of segments displays generally
equal strength in all directions, i.e., generally isotropic. Also,
any segment can be made arcuate by slight alteration so as to curve
along its length.
Fabrication of the cells, segments, and structural components may
be effected in a substantially continuous process, as previously
indicated, in which a continuous web of flat, planar material is
scored after being withdrawn from a supply roll. The requisite
scoring of the web to permit the same to be folded may be of any
conventional type, and may include perforating the web or forming
lines of weakness therealong, although this technique is not
preferred because it evidently detracts from the structural
strength of the end product. However, such techniques may be
satisfactory depending upon the strength requirements of any
particular environment in which a structural component is to be
used.
While in the foregoing specification embodiments of the invention
have been set forth in considerable detail for purposes of making a
complete disclosure thereof, it will be apparent to those skilled
in the art that numerous changes may be made in such details
without departing from the spirit and principles of the
invention.
* * * * *