Note: Descriptions are shown in the official language in which they were submitted.
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TRUSS PANEL
BACRGROUND OF T~IE INVENTION
The present invention relates to a method
and apparatus of forming moldable integrated truss
structures and to composite structures resulting
from incorporating such truss structures between
outer framing elements, sheets, skins or by
incorporating strengthing structures within the
truss structures.
Numerous efforts have been made in the past
for providing improved truss structures and for
reducing the time and expense involved in manufac-
turing such truss structures~ As is known in the
art, truss structures typically are utilized to
provide support for a thin material such as a
metallic skin, a floor, roof or wall or other such
surfare which is not capable by itself of supporting
shear, bending and axial loads in various
directions. Most truss structures, are formed of a
plurality of diagonal strut members which are joined
together by means of rivets, welds, or a nut and
bolt arrangement. Examples of such prior art truss
structures may be found in Bunker, U.S. Patent
2,123,931 and Troutner, U.S. Patent 3~541,749. In
each of these patents, a truss structure is
disclosed which requires a substan~ial amount of
labor to join the strut beams to one another to
provide a truss which is capable of supporting
forces acting thereagainst. Another example of such
a truss structure is disclosed in Snyder et al, U.S.
Patent 3,415,027 wherein an unsymmetrical truss
structure is formed of a plurality of steel beams
which must be joined to one another by means of a
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riveting process which requires a substantial amount
of labor.
Kastan disclosed in U.S. Patent 2,791,386 a
symmetrical truss structure having a plurality of
strut elements joined at bosses at the top and
bottom of the truss. The truss structure is capable
of transmitting shear, bending and axial loads in
any direction and is used for the cores of aircraft
wings, structural panels and box type structural
beams. There is no disclosure of a method of
forming this truss stru~ture as an integral unit,
such as, by means of an injection molding process~
Other forms of reinforcing structures are
illustrated in Pajak, U.S. Patent 2,609,068 and
Plumley et al, U.S. Patent 2,849,758 wherein a
honeycomb structure is disclosed. The drawbacks to
a honeycomb structure are that substantial manual
labor is required to join the honeycomb elements
together and once formed it is difficult to provide
an insulating means for the structure if such is
desired~ i.e. insulation or ~oam cannot be injected
through the honeycomb structure to provide an
insulation medium.
Each of the aforementioned types of truss
structures have the drawback that each require a
relatively large amount of manual labor for forming
the truss structure which inherently drîves up the
cost of such structures. ~herefore, there is a need
in the art for a simplified truss structure which
can be formed with a minimum o labor to thereby
reduce the cost of such structures. Patents which
show types of mold structures include Schavoir, U.S.
Patent 1,409,591, Yellin, U.S. Patent 2,566,817,
Cohan, U.S. Patent 3,333,300, Karlyn, U.S. Patent
3,790,371, Taketa, U.S. Patent 3,871,611 and
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Lipscomb, Canadian Patent 883,932.
It is another objec~ of this invention to
provide an apparatus for forming an integrated truss
structure.
SHORT STATEMENT OF_THE INVENTION
Accordingly, this invention relates to
molds for forming integrated truss structures
wherein such molds are comprised of two mold
portions each including a plurality of male and
female mold members. ~he male mold members each
have a plurality of open grooves which may be
orthogonally disposed with respect to one another or
in the alternative may be disposed at 60 angles
with respect to each other when viewed in a
direction normal to the plane of the skin supported
by the truss. The range of angles can be from about
30 to about 75 with a preferred angle being about
45U. The grooves slope away from the top surface of
the mold member. Each of the female mold members
have a generally recessed cavity with a plurality of
open grooves aligned to mate with the grooves in the
male mold members. These grooves slope away ~rom
the plane of the recessed cavity. The male and
female members are positioned opposite one another
with the groove~ in the male and female members
being aligned to define strut beam chambers and with
the top of the male member being aligned with the
recessed cavity of the female member to define a
junction chamber. The male members are each
positioned adjacent a female member, and vice versa,
to thereby define alternate symmetrical upper and
lower junction chambers interconnected by the strut
beam chambers. When the mold portions are placed
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toge~her the chambers defined thereby are all
interconnected and a means is provided for injecting
a moldable material throughout the chambers to
thereby form an integrated, integral, truss panel.
S In an alternate embodiment, integrated male
and female mold members are formed~ In this
embodiment, a first fixed mold member includes a
plurality of spaced, raised flat portions together
with a plurality of spaced, recessed flat portions
and a plurality of open grooves connecting the
raised and recessed portions. A second movable mold
member includes a plurality of spaced, raised flat
portions and a plurality of spaced recessed flat
portions with a plurality of open grooves connecting
the raised and recessed portions. The mold members
are positioned in opposing relationship with respect
to one another wherein the raised portions of the
first member are aligned with the recessed portions
of the second member and vice versa. The alignment
of the raised and recessed portions define a
junction chamber and the aligmnent of the open
grooves define the strut beam chambers. An
injection menas is provided for injecting a moldable
material into the thus formed chambers.
The present application also relates to
various forms of such integrally molded truss
panels. In one preferred exemplary form the
junctions of each of the plurality of strut beams
comprises a disc or junction plate. Since there are
a plurality of such junction plates or contact
points appearing on the outer, substantially planar,
top and bottom surfaces of each of the truss cores
used to form panels formed according to the present
invention, such points together form the top and
bottom outer sides of such cores. Accordingly, the
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presence of such junction plates provides a
relatively large surface area which can be used when
welding or adhesively or mechanically securing outer
sheets or other outer structures at desired
locations on the truss panel.
In alternative embodiments t the strut beams
can ter,omate at ~he top and bottom surfaces of the
~russ panel or, on the sides of hollow, annular
bosses~ Still another embodiment concerns providing
a hole within the center of the junction plate. The
structures that include such holes or hollow~
annular bosses then can permit the securing of
exterior structres by gluing as well as by nails,
screws, rivets or other mechanical means. Another
arrangement includes the use of support saddles or
channels into which the strut beams extend and in
which they are secured. Thus, the saddle or channel
would be designed with a particular cross-sectional
profile suitable to receive a particularly shaped
member therein.
The present invention also includes a
variety of approaches to strengthen truss panels
including the securing of outer sheet members or the
incorporation of open grid type structures.
BRIEF_DESCRIPTION OF THE DR~WINGS
Other objects, features and advantages of
the present invention will become more fully
apparent from the following detailed description of
the preferred exemplary embodiments, the appended
claims, and the accompanying drawings in which:
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FIGURE 1 is a plan view of one exemplary
integrated truss structure formed by the method and
apparatus of the present invention;
FIGURE 2 is a side elevation view of the
truss structure of FIGURE l;
FIGURE 3 is a section view taken along the
lines 3-3 of FIGURE 20f a strut beam of the truss
structure formed by the method and apparatus of the
present invention;
FIGURF 4 is a plan view of a male mold
member for forming a truss structure;
FIGURE 5 is a section view taken along the
lines 5-5 of Figure 4 of the male mold member;
FIGURE 6 is a plan view of a female mold
member for forming a truss structure;
FIGURE 7 is a section view taken along the
lines 7-7 of FIGURE 5;
FIGURE 8 is a simplified section vie~ of
three sections of the mold for forming the truss
structure;
FIGURE 9 is a partial perspective view of
this truss structure formed by the method and
apparatus of the present invention;
FIGURE 10 is a partial perspective view of
an alternate embodiment of a truss structure formed
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by an alternate molding apparatus of the present
invention;
FIGURE 11 is a section view illustrating
the opposed male and female members for forming the
5 truss structure of FIGURE 10; and
FIGURE 12 is an alternate truss structure
having an interlaced strut beam structure capable of
being formed by the method and apparatus of the
present invention.
FIGURE 13 is a diasrammatic view of a
portion of another truss structure embodiment
capable of being formed by the method and apparatus
of the present invention;
FIGURE 14 is a cross-section view of a
modified form of a male mold member for forming the
truss structure of Figure 13;
FIGURE 15 is a cross-section view o~ a
modified female mold member for forming the truss
structure of Figure 13;
FIGURE 16 is a diagrammatic view of a
portion of another truss structure embodiment
capable of being formed by the method and apparatus
of the present invention;
FIGURE 17 is a cross-section view illus-
trating opposed male and female mold members used to
form the truss structure of Figure 16;
FIG~RE 18 is a diagrammatic view of a
portion of 5till another truss structure embodiment
capable of being formed by the method and apparatus
of the present invention
FIGURE 19 is a cross-sectional view
illustrating opposed male and female mold members
used to form the truss structure of Figure 18;
FIGURE 20 is a diagrammatic view of a
portion of another truss structure embodiment
capable of being formed by the method and apparatus
of the present invention in which the support points
extendin~ in one direction have been moved closer
together;
FIGURE 21 is a diagrammatic top plan view
of a portion of a truss formed according to the
present invention having a wooden beam structure
provided on its top and bottom surfaces;
FIGURE 22 is an end eiew of the truss
structure embodiment of Figure 21;
FIGURE 23 is a side elevational view of the
truss structure embodiment of Figure 21;
FIGURE ~4 is a modification of the truss
structure of Figure 21 in which the double beams
extend diagonally;
FIGURE 25 is a diagrammatic top plan view
of one contact point of a truss structure made
according to the present invention showing a portion
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of a lattice of rods forming one of the outer
surfaces of a panel secured thereto;
FIGURE 26 is a diagrammatic side
elevational view of a grooved contact point of a
truss structure made according to the present
invention;
FIGURE 27 is a diagrammatic top plan view
of a portion of a truss structure according to the
present invention incorporating the support system
shown in Figure 25;
FIGURE 28 is a diagrammatic top plan view
of a portion of a structural panel structure
including an internal truss structure made according
to the present invention;
FIGURE 29 is a cross-sectional view taken
along line 29-29 in Figure 28;
~ IGURE 30 is a diagrammatic perspective
view of another structural panel incorporating a
truss structure made according to the present
invention;
FIGURE 31 is a diagrammatic end view of
another structural panel incorporating a truss
structure made according to the present invention;
FI~URE 32 is a diagrammatic perspective
view of a corner member, with portions cut away for
clarity, for use with structural panels incorpora-
ting truss structures made according to the present
invention;
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FIGURE 33 is a diagrammatic side eleva-
tional view of a skylight structure incorporating a
truss structure made according to the present
invention;
FIGURE 34 is a diagrammatic cross-sectional
view of a solar collection panel incorporating a
truss structure made according to the present
invention;
FIGURE 35 is a diagrammatic cross-sectional
10 view of a portion of structural panel incorporating .
a truss structtlre made according to the present
invention showing an exemplary fastening mechanism
for securing an outer panel to the truss structure.
FIGURE 36 is a perspective view of another
alternative embodiment of the present invention;
FIGURE 37 is a ~ide elevational view of the
embodiment shown in Figure 3~;
FIGURE 38 is a side elevational view of a
composite structure formed by superimposing two of
the structures shown in Figure 37; and
FIGURE 39 is a side elevational view of a
curved composite structure embodying the structure
shown in Figure 37.
DETAILED DESCRIPTION OF THE PREFERRED EXEMPLAR~
EMBODIMENTS
The present invention will now be described
in connection with the exemplary preferred
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embodiments. BeEore describing the apparatus for
forming a truss structure, reference is first made
to Figures 1-3 where an exemplary embodiment of a
truss structure, formed by the method and apparatus
of the present invention is illustrated. The truss
structure includes a plurality of symmetrically
disposed junction plates 11 which are alternately
positioned on the top and bottom of the truss. Each
of the junction plates ll are joined to an adjacent
junction plate positioned on the opposite side of
the truss panel structure by means of a plurality of
strut beams 13. The strut beams 13 may be formed of
a single element or, as illustrated in Figure 1, a
pair of elements 13 can be joined together by means
of an internal web 15. Strut beams 13 extend
outwardly away from junction plates ll and are
joined at adjacent junction plates on the underside
thereof as illustrated. As illustrated, the strut
beams are orthogonally disposed with respect to one
another. However, it should be understood that
three beams could extend outwardly from the junction
plates at e~ual angles with respect to one another
if desired. Other beam configurations are possible
in keepiny with the concept of the present
invention~ Each junction plate 11 is formed with a
substantially flat exterior surface so that an outer
skin or skins 10, such as a metallic or plastic
plate wood sheet or other natural or synthetic board
can be attached thereto by suitable means, such as,
for example, glue, electromagnetic bonding, rivets
or screws. If rivets or screws are to be used to
secure the skin to the truss structure, holes 62 are
formed in the junction plates 11 as illustrated in
Figure 10. It should also be noted that the outer
surface of junction plates ll together cooperate to
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form the outer, substantially, planar, top and
bottom surfaces of the truss panel. Further, while
only a small truss structure is shown in Figure 1,
it should be understood that it is representative of
such truss panels includes a repeating design unit
indicated within the s~uare formed from phantom
lines. By having this design unit repeated, truss
structures of various sizes and dimensioned can be
molded as integral structures.
The material used for forming truss
structures according to the present invention may be
any plastic material including, thermoplastics, such
as polyolefins, polycarbonate or nylon, etc.,and
thermosetting materials or reinforced plastic
materials, polyethylene or polycarbonate. In fact,
the structure could be formed of any plastic or
metallic materials, such as aluminum, for which mold
material is available to withstand the temperature,
pressure and other requirements for molding same.
Figures 4 and 5 illustrate one of a
plurality of male mold sections used in the mold
when forming an integrated truss structure. As
illustrated in Figure 4, the mold includes a metal
molding block formed, for example, from beryllium
copper castings. The beryllium copper castings are
subjected to several thousand pounds per square inch
pressure while solidifying the mold. Beryllium
copper is advantageous because of its good heat
conducting properties which result in a fairly rapid
and uniform cooling of the mold after the hot
plastic or metallic material which is to form the
truss structure is injected into the mold. The male
mold member 17 has four orthogonally disposed
grooves 19 formed therein which slope downward~y and
away from a plateau 21. In the preferred embodi-
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ment, the grooves slope away from the plane of theplateau 21 at a strut angle of approximately 45,
although it should be appreciated that the strut
angle can be varied depending upon the structural
requirements of the panel or skin which the truss
s~pports. It further should be understood that this
angle can be different in one direction than in an
orthogonal direction. Thus, with reference to
Figure 1 the junction plates 11 in one direction
would be closer together than in a direction at a
right angle thereto.
The male member 17 has an upper surface 23
which as will be seen mates or engages the recess
cavity in the female mold member to define a
junction chamber for forming the junction plates
11. The male member also includes a mold bearing
surface 25 which bears against the corresponding
surface on the female mold members to define the
molding position of the male and female mold
members. Referring to Figure 5, which is a cross~
sectional view of the male mold member taken along
the lines 5-5 thereof, the grooves 19 are shown
sloping downwardly away from th,e plateau 21 at about
a 45 angle. The top surface 23 extends upwardly
from ~he plateau 21 and forms the mold surface for
the underside of the junction plates 11. The male
mold member is fixedly secured to a support plate
(not shown) by means of, for example, one or more
screws which are inserted into the hole 27 formed in
the base of the male mold member or by any other
known techniques which will securely hold the mold
member in place. A suitable alignment means such as
a dowel can be utilized to insure that each mold
member is positioned on the support plate directly
opposite its mating member. It should be
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appreciated that cooling channels could be formed in
the mold member for the purpose of carrying the heat
of the molten plastic or metal away from the mold
block to thereby ~acilitate the cooling of the
molded material.
Reer now to Figures 6 and 7 where there is
illustrated a female mold block. The female mold
block 29 includes a recessed cavity 31 having a
plurality of grooves 33 extending upwardly, and away
therefrom at about a 45 angle with respect to the
plane of the bottom surface of the recessed
cavity. The mold block as illustrated in Figure 7
has an upper bearing surface 35 which bears against
the surface 25 of the male mold member 17 when the
two bloclcs are positioned one opposite the other in
preparat:ion for injecting a mold material there.
The female mold block 29 is sec:ured to a base
support plate (not shown) by means of one or more
screws which are inserted into the threaded holes 37
or securement can be achieved by other techniques
known in the art. As aforementioned, the female
members can be aligned by a suitable means, such as
dowels, to insure the proper alignment with the
mating male member. The male and female mold blocks
when positioned opposite one another in a mating
rela~ionship define a junction chamber and plurality
of strut beam chambers.
In order to facilitate separation of the
male and female mold members, the cone angle, i.e.,
the angle at which the sides 20 and 22 of the male
and female members, respectively, slope with respect
to the axis of the mold travel, is made a suitable
size which may vary depending upon the temperature
and mold materials utilized. However, this angle
preferably should not be so great that the side wall
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22 of the female member intersects the side wall of
the mold below the mating established by the mold
bearing surfaces 25. It should also be appreciated
that the grooves must have a draft, i.e., slightly
inclined walls, so that the molded truss structure
can be easily removed from the mold members.
A molding material such as a plastic or
metallic material is injected into the female mold
via channel 39 and then into the recessed cavity 31
when the female mold member and the male mold member
are positioned opposite one another.
Referring now to Figure 8 where there is an
ilustration of how the respective male and female
members are aligned to obtain the truss structure
illustrated in partial perspective in Figure 9. As
illustrated in Figure 8, male and female mold
members are positioned alternately with respect to
one another so that a female mold member is
positioned adjacent each male mold member and vice
versa. Thus, female mold member 29 has positioned
against each of its sides a male mold member 17 to
thereby form a first lower mold member 43a having a
plurality of raised plateaus 21V and a plurality of
spaced recessed flat portions 31 each connected by
means of open grooves 19 and ~3O A second plurality
of male and female members are joined together to
form a second upper mold member 43b that is ver-
tically movable with respect to the first mold
member 43a. This mold member also has male and
female members alternately positioned against one
another as illustrated to define a plurality of
raised cavities 41', and a plurality of plateaus
21', each joined together by means of open grooves
19' and 33'. In the preferred embodiment, the
bottom mold is formed by joining a plurality of mold
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members by ixedly securing these members to a base
plate (not shown). The upper mold 43b is also
joined to a support plate (not shown), but is
movable with respect to the lower mold so that once
the mold material is injected into the mold, the
upper mold can be moved away from the lower mold to
thereby free the truss structure for removal of the
mold. When the upper mold 43b is moved into
position with respect to the lower mold 43a, the
bearing surfaces 25 and 35 serve to define the final
position of the upper mold with respect to the lower
mold. ~hen this occurs, a plurality of strut beam
chambers ~1 are formed from the open grooves 17,
17', 19 and 19'. In addition, a plurality of
junction plate chambers 53 are formed by means of
the recessed cavities 31, and the upper surface 23
of the male mold members~ The moldable material,
plastic or metallic materials, is injected into the
strut beam chambers and the junction plate chambers
thus formed tbrough annular channel 39. The channel
39 is preferably formed in one or more of the female
mold members which are secured to the bottom support
plate. If desired, a heating element can be
positioned in one or more of the female mold members
which are utilized for injecting plastic or other
mold materials for the purpose of maintaining the
temperature of the molten mold material at a
substantially uniform high temperature.
After the molten mold material has been
injected into the chambers defined by the upper and
lower molds, the upper mold is removed away from the
lower mold with the truss structure illustrated in
partial perspective view in Figure 9 resulting
therefrom. In Figure 9, a plurality of junction
plates 11 are formed, each spaced symmetrically with
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respect to one another and with respect to the junc-
tion plates 11' on the opposite side of the truss
structure. Each of the junction plates are joined
to one another by means of strut beams 13 which are
integrally molded with junction plates 11 and 11'.
As illustrated in Figure 9, each strut beam is a
single beam, however, it should be understood that,
in keeping with the present invention, by a simple
modification of the mold structure a double or I-
beam structure could be provided such as illustratedin Figures 1-3.
If desired, rather than forming the upper
and lower mold halves from a plurality of separate
male and female mold members, a single mold member
could be formed. This would require appropriate
machining in order to insure that plateaus 21,
recess cavities 41, and the open grooves were all in
alignment with respect to one another when the mold
is closed.
In such an integrated mold structure the
cone angle should not be greater than the angle
formed by line 50 shown in Figure 8 extending from
the edge of one recessed cavity 41 to the edge of an
adjacent oppositely disposed cavity 41. This will
enable the male and female cones not to be truncated
on their sides.
Alternatively, mold modules could be formed
from a group of individual molds with each mvld
group, perhaps, having a different but compatible
design. A plurality of such molds could be
assembled together and would thus make up a complete
mold structure. This has the benefit of avoiding
cumulative dimensional error which could result from
making a large integral mold.
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In the present case, individual male and
female mold members were joined to one another on a
base plate to form the upper and lower mold members
because of the simplicity of the structure thereof
and because of the flexibility of size of the truss
structure which can result by adding or subtracting
male and female members from the upper and lower
mold members.
Referring now to Figures 10 and 11 where
there is illustrated an alternate embodiment of the
apparatus of the present invention for forming a
truss structure having hollow annular bosses 61
which permit the use of rivets, screws or inserts to
fasten a skin material to the truss structure. The
annular bosses may also be provided in a panel where
the junction plates are adhered or welded to the
skins. In this case the bosses provide strony
points for attaching other structures to the panel
by fasteners such as screws or blind rivets. Thus,
as illustrated in Figure 10, the truss structure is
formed of a circular junction plate 63 having a flat
upper surface or skin attachment surface 6~ with the
junction plate having a hole 62 through the center
thereofO On the underside of the junction plate 63
is formed an annular, hollow boss 61, which serves
as a reinforcement for the junction of the strut
beams 13 and the junction plate 63. Su~h a truss
structure may be formed from a mold comprising a
plurality of male and female mold members of the
type illustrated in Figure 11. Thus J as is
illustrated in Figure 11, a female mold member 67,
is of the same design as the female mold member of
Figures 6 and 7 with one important exception. The
exception relates to the manner in which the molten
moldable material is injected into the chambers
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defined by the juxtaposition of the male and female
mold members. Thus, since a hole 62 is to be formed
through the junction plate 63~ no molten material
can be injected into this region of the truss
structure. Thus, the point at which the mold
material is injected into the mold must be orf-
center from the center of the recessed cavity 69 as
illustrated in the figure.
The male mold member 71 includes a
plurality of open grooves 73 together with a plateau
surface 75, and an upper sur~ace 77. However, a
center post 79 must be formed either in the male
mold member 71 or the female mold member 67 or in
both in order to define a circular area about which
the moldable material flows but by which no moldable
material can flow into a cylindrical air volume
defined by the post 79. This volume results in the
formation of the hole 62 in the junction plate 63.
As aforementioned, in connection with the descrip~
tion of the composite mold structure of Figure 8, a
plurality of mold members are joined to one another
with the female and male mold members being juxta-
posed alternately to thereby define upper and lower
mold members. In the alternative, rather than
providing a plurality of male and female mold
members which are fastened onto a back plate ~ext to
one another, an integral upper and lower mold member
may be machined to have the same configuration as
the plurality of juxtaposed male and female mold
members.
Refer now to Figure 12 where there is
illustrated a high strength truss structure having
an interleaved truss core structure. The molded
truss structure of Figure 12 is formed by simply
joining together two truss structures of the type
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illustrated in Fiqure 9. Such truss structures can
be joined together by any suitable means known in
the art such as for example, by the use of adhesive
compounds. As a result of joining the two truss
structures, it can be seen that twice as many strut
beams can be provided for a given thickness of the
truss structure as would be possible if the two
truss structures were not joined together. Thus,
with reference to Figure 12, shown in dotted lines
is the strut beam structure which would result from
a truss beam formed from a single moldO It can
readily be seen that by fixing one truss structure
with respect to another that twice as many junction
plates 11 per unit length are provided parallel to
the skin or surface supported by the truss and twice
as many strut beams 13 are formed as would
ordinarily be formed by a sin~le molding step
utilizing the same strut angle. The buckling
resistance of the skins 82 and 84 will be increased
because of the increased closeness of the junction
plates 11 or in the alternative thinner skins can be
used~
~ he lamination or joining of truss struc-
tures can be increased in number beyond two as
required for strength, stiffnessr or other require-
ments. Intermediate skins may be attached between
the layers in addition to the outer skins for
various purposes such as improved thermal insulation
in translucent panels or reduced radiant heat
transmission if reflective surfaces are employed.
Turning now to Figure 13 another exemplary
embodiment of the truss structure according to the
present invention is shown. This structure differs
from the truss shown in Figure 9 in that junction
plates 11 have been removed so that strut beams 13
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now join together direc~ly to form a cross-shaped
junction elemtn having an upper or exposed surface
100. while the upper edge of strut beams 13 can
directly join or intersect surface 100 a step
indicated at 102 is provided between surface 100 and
the inserting point of the upper surface of strut
beams 13. Thus, as was the case in Figur~ 9 with
respect to junction plates 11 which appeared in one
planar surfacP of the truss structure and junction
plates 11' that appeared in the opposing planar face
of the truss structure so two alternating faces 100
will appear in both the upper and lower surfaces of
the truss core structure and cooperate together to
form substantially upper and lower planar faces of
the truss structure. I have found that in some
instances the bonding surface provided by junction
plates 11 and 11' is not necessary and that smaller
bonding surfaces such as are formed in Figure 13 at
100 is all that is required for joining the truss
structure to various ~ypes of surface members
including outer skins or structural webs. Further,
this modified truss structure as shown in Figure 13
can be used advantageously as a dividing screen or
can be used with other like truss elements of a
predetermined size to form a protective panel as,
for example, a machinery guard. The truss structure
produced as shown in Figure 13 could be bonded by
suitable adhesives to transparent sheets to
produce a self-supporting guard which allows
observation of the machineO Vision could be further
enhanced if the material from which the truss core
were made were a clear plastic such as clear
polycarbonate.
The modified truss structure shown in
Figure 13 is produced by the use of opposed male and
~3~2
22
female members 17a and 29a respectively shown in
Figures 14 and 15. These members differ from mold
members 17 and 29 shown in Figures 5 and 7 in that
the upper surface 23 has been extended away from
plateau 21 a distance corresponding to the height o
,step 102 and this added section is shown generally
by the bracket indicated at 104. Recessed cavity
31' of female mold member 29a differs from cavity 31
shown in Figure 7 in that it has been modified in
order to receive the added section 1040 In order to
produce the stepped structure shown in Figure 13
with step 102 grooves 33 would terminate prior to
the bottom of cavity 31'. If, however, the top
surface of strut beams 13 extended to surface 100
then grooves 33 would extend all the way to the
bottom of cavity 31'. Alternatively the bottom of
that cavity could be raised so that it directly
intersected the termination point of grooves 33 as
shown by the dotted line 32 in Figure 15.
Turning now to Figures 16-19 Figures 16 and
18 show two alternative forms of the structure set
forth in Figure 10 which sets forth a truss
structure according to the present invention. This
truss core structure is provided with a modified
type of hollow angular boss 61' that forms an
integral structure with the ends of strut beams
13. In Figure 10 ~he angular bosses 61 were
provided with junction plates 11 which had an
opening or hole 62 that extended not only through
boss 61 but also through plate 11. The junction
plate 11 has been removed from both embodiments
shown in Figures 16 and 18 as there may be many
instances where that plate and the bonding surface
provided thereby are not needed. In Figure 16 the
tops of strut beams 13 extend upwardly to a height
~9~:~'2
23
equal to the exposed exterior surface of boss 61' 50
that on both sides of the truss structure the
substantially planar sides of that structure are
formed by those upper surfaces of the struts as well
as the surface 108 of annular boss 61'.
The mold members for producing the
structure set forth in Figure 16 is shown in Figure
17 and are each comprised of a plurality of male and
female mold members as shown at 71 and 67,
respectively. These members can be compared with
Figure 11 and it can be seen that the recessed
cavity 69 as shown in Figure 7 has been removed from
the mold structure shown in Figure 17 since it is
the cavity 69 in which junction plate 11 is formed
about center post 79. Likewise, the length of
center post 79' has now been reduced from the length
needed in Figure 7 but the post 79' still meets or
engages the bottom surface of the cavity within
female mold structure 67 50 that hole 62 is formed
in a manner that allows it to extend completely
through angular boss 61'.
It should be understood that the annular
bos 61' could be formed without hole 62 simply by
omitting post 79l from the mold.
By forming the strut beams 13 with respect
to angular bosses 61' in this manner I have found
~hat it is possible to have the axis of each of the
strut beams 13 arranged in a way such that they can
intersect the plane o~ the neutral axis of the
surface members attached to the truss core
structure, including lattice structures or sheeting
materials applied to thé exterior of the truss
structure. For example, if relatively large trusses
having dimensions four feet by eight feet or eight
feet by sixteen feetare formed in the manner as
3~9~1L2
2~
shown in Figure 16, it is possible to apply exterior
sheeting materials such as insulation panels,
plywood sheets, gypsum board or other common
building materi.als to the exterior of this truss
structure either by gluing those materials to
exposed surfaces 108 or by employing screws or nails
that would fit within holes 62 or if the exterior
sheet material were metal, that material could be
attached to the truss structure by means of welding
to surface 108 or angular bosses 61' or by riveting
throuqh hole 62. It should also be pointed out that
while strut beams 13 have been shown as having a
substantially rectangular cross-sectional shape such
strut beams could be provided with a round, square
or relatively flat cross-sectional shape as well
depending upon the materials used to make the truss
structure and the purpose for which the truss
structure is going to be used.
In Figure 18 the strut beams 13 intersect
angular bosses 61" so that the angular boss 61"
extends up from the point where the top surface of
strut beams 13 intersect the outer side wall of the
boss 61". Thus, a portion of the hollow boss
extends above strut beams 13 as indicated by bracket
110.
The mold elements used to construct the
truss structure shown in Figure 18 are set forth in
Figure 19 and again differ from the members shown in
Figure 11 in that the portion of cavity 69
surrounding the area in which angular boss 61 is
formed is now filled by raising the bottom surface
of the inner cavity of female mold member 67a.
Specifically, with reference to Figure 19 the
centrally located post 79" is still provided between
plateau 75 of the male mold member 71 and the bottom
~3S~%
surface of the recessed cavity within female mold
member 67a. The recessed area within female mold
member 67a is now made up of two surface levels an
upper one indicated at 112 and a lower one at 114.
Between these two levels is an annular vertical
surface indicated at 116 which meshes with an
annular surface 118 provided in the male mold member
71a so that it extends vertically away from the
boundary established by plateau surface 75. When
the male and female mold members are together, as
shown in Figure 19, vertical annular surfaces 116
and 118 meet and form, together with post 79", an
annular chamber which forms the annular hollow boss
61". Surfaces 112 and 114 serve to define the upper
surfaces 120 and 122 respectively of the strut beams
13 and annular boss 61n. As was the case with the
mold members shown in Figure 11 the injection point
for the molding material must be offset from the
center of the cavity existing between the two mold
members and accordingly the injection groove 124
shown as being offset from post 79".
Here again, by moving the axes of strut
beams 13 it is possible here to also design
different sized hollow annular bosses 61" so that
the intersection of those axes can be moved toward
and away from the substantially planar surface
established by ~he plurality of surfaces 122 on both
top and bottom sides of the truss structure. I find
it to be advantageous to have the neutral axis of
any sheets secured to the truss structures be
intersected by the axis of the strut beams as this
reduces the generation of any additional bending
moments following the completion of a panel
structure comprised of two parallel sheets secured
to the opposite sides of the truss structure made
~L3~L2,
26
according to the present invention. Such a
structure is set forth in Figure 12. In that figure
two truss structures have been incorporated within
the panel structure but such panel struc~ures could
include only one truss structure or could include
more than the two. Likewise, as was previously
indicated the dotted line representation in Figure
12 sets forth what the panel structure would look
like if only a single truss structure were
incorporated between the two sheets 82 and 84.
Thus, for given thicknesses of sheet structures that
are to be placed on the exterior of the truss
members truss structures can be molded with the axes
of the strut beams designed so that they will
intersect at the neutral plane of the particular
thickness of the surface member.
Turning now to Figure 20 another
alternative exemplary embodiment of a truss
structure according to the present invention is set
forth. I found ~hat in some instances it would be
desirable to have the contact surfaces or points
formed where the s~rut beams 13 intersect in each
side plane of the truss structure lie closer
together in one direction than the other. For
example, when manufacturing curved panel structures
where a truss structure made according to the
present invention is subsequently put into a press
to develop a predetermined amount of curvature in
the truss structure following which the truss
structure was then incorporated between two
similarly curved outer plates,it would be
advantageous to at times concentrate the number of
contact points in certain areas. Such panel
structures could be used when making a wide variety
of curved structures including the side wall members
~13g9~2
27
for automobiles or airplanes, boat hulls,
etcetera. At the point where the greatest curvature
exists it would be desirable to have contact points
lying closer together and I have found that this
could be accomplished by spacing the contact points
126, which appear on and define one of the planar
surfaces of the truss structure shown in Figure 20,
at equal distances spaced from one anotber at the
corners of an equilateral triangle. The contact
points 128 appearing on and defining the opposite or
bottom planar surface of the truss structure shown
in Figure 20 would then be offset half the distance
between points 126. Thus, if the distance between
points 126 along a horizontal row equal to 5, the
distance between vertical rows would be 0.5S. The
distance between horizontal rows, or the height of
the equilateral triangle, would be equal to the
square root of 0.866S. Thus, the horizontal rows
would be spaced the square root of 3 times further
apart than the vertical rows. Thus, by making
similar kinds of changes with respect to the spacing
between points 126 and 128 the contact points
appearing in both surfaces cou:Ld be modified to suit
the particular needs of the structural panel being
produced.
Turning now to Figures 21-24 another
alternative embodiment of a structural panel
incorporating the truss skructures made according to
~he present invention is set forth. The truss
structure is indicated in Figures 22 and 23
generally at 130 is comprised of struts 132 which
tie together and are integrally molded with
rectangular shaped pad elements. For ease of
explanation the rectangular pads appearing in the
top and bottom surfaces respectively of the truss
2~
structure 130 are indicated by numerals 134 and
134', respectively. As indicated in Figure 1, each
of the pads 134 and 134' have an open channel or
saddle 136 formed between two upwardly extending
side p.ieces 138 and 140. This channel, 136 can
receive a panel surface member such as, for example,
a lattice structure which begins with a wood strip
142 which can be glued or in any other convenient
manner secured within channel 136. As shown in
Figure 21 channels 136 extend in what would appear
to be the vertical direction and accordingly in this
embodiment wood strips 142 would extend on one side
of the structure from one pad 134 to the next pad
134 and so on along the length of that side.
As shown in Figures 22 and 23 the next
layer of the lattic structures formed from a
plurality of second wooden strips 144 positioned
orthogonally with respect to strips 142.
I have found that for a panel having
dimensions approximately by eight ~8) feet by
sixteen (16) feet having the distance between the
neutral axis of the lattices second to the truss
core beins about eight t8) inches, the panel being
designed for forty (40) pounds per square foot using
hardwoods, the dimensions for wood strips 1~2 can
preferably be about 1 inch wide by 5/8 inches thisk
whereas the dimensions for wood strips 144 can be
approximately 2 inches wide by approximately S/8
inches thick. Wood strips 144 can be secured to the
panel and specifically at the cross points with wood
strips 142 by any convenient means such as by screws
or glue and together serve to provide additional
resistance to bending and shear forces to each side
of the panel.
~3~9~
29
While the structure could incorporate only
wood strips 142 and 144 I have ~ound that it would
be preferable to complete the lattice structure by
including a third group of a plurality of additional
wood strips 146 identical to wood strips 142,
running in the same direction as wood strips 142 and
overlying strips 142 and 144. Again, wood strips
14Ç can be secured to the structure by glue or any
other convenient means such as by screws or bolts,
and the finished structure produces a building panel
to which a wide variety of additional surface sheet
structures could be applied either by nails,
staples, glue or other conventional means.
It should also be understood that both the
top and bottom sides of the panel structure can be
formed as just described with respect to the
application of wood strips 142-146 and these are
indicated in Figures 22 and 23 respectively by
reference numerals 142', 144' and 146'.
It should also be understood that the
resul~ing building panel as shown in Figures ~1-23
could be filled with various types of thermal
insulating materials. For example, the truss panel
structure could be filled with a foam insulator or,
alternatively, following the securing of a surface
sheet to one side of the panel, such as a piece of
gypsum board or plywood, the entire structure could
thereafter be filled with a foam insulating material
or blown insulation of various types. Thereafter,
the second or top skin could be attached which would
hold the insulation in place within the panel
structure. Additionally, as discussed more fully
hereinafter, the resulting panel structure could
also be provided with end or side pieces so that the
resulting building panel could be enclosed not only
~3L3~3~
from the top and bottom by skin material secured to
the cross members 142-146 but also by the side or
- end pieces that would close off the remaining
exposed open portions of the panel.
Turning now to Figure 24 the truss
structure would remain the same except that the pads
formed by the junction points for the struts would
be changed in configuration so that wood strips 142
are placed diagonally. Wood strips 144 are applied
there over as in Figure 16 while wood strips 146 are
also applied diagonally across the top of strips
144. The angle between diagonal members 142 and 146
can vary widely but the preferred range is about
30to about 90. The form of the pads appearing on
this modified truss structure are shown at 148 in
the upper surface and 150, with pads 148 appeariny
on the upper surface of the structure while pads 150
appear on the lower or bottom surface. Each pad is
again provided with an open channel or saddle area
2~ 152 which i~ formed between twc> upwardly extending
triangular portion 154 and 156.
Only the bottom wood strips 142 fit within
pads 148 and 150 with wood strips 144 and 146 being
bonded respectively to wood strip 142 and 144. The
bonding between the wood strips can be effected by
adhesives or by using mechanical fastening
techni~ues.
It should be pointed out, that while
discussing the embodim~nt set forth in Figures 21-24
while wood strips have been specifically referred to
other structural members such as plastic strips,
metal beams, or some type of laminated structure, or
wires could likewise be used with the shape of the
saddle or the pad area being changed to effectively
3 l
support and secure the supporting member to the
truss structure.
The diagonal embodiment set forth in Figure
24 produces a truss panel structure which exhibits
extremely good stress resistance with respect to
both bending and shear forces and because of the
presence of the diagonal members would be
exceptionally well suited for use in building roof
or wall structures.
When employing a grid of wires as the
surface member in the truss panel, it would be
possible to form the pads 162 appearing at ~he end
of the struts 13 as shown in Figure 26, with slots
or grooves 15S and 160 within the upper surface.
Grooves 158 and 160 are shown as being perpendicular
to each other and crossing in the center of the pad
although they could be varied to suit the sur~ace
member being usedO With such a structure, it is
possible to incorporate cross wires 164 and 166
respectively within grooves 158 and 160~ The pad
could also include the junction plate 11 which in
certain circumstances would provide a greater
surface to which the wires or a subsequent outer
skin could be secured and likewise such a junction
plate might provide additional plastic material when
securing wires 164 and 166 in place. I have found
that it is preferable to have the wires welded
together at their crossing points so that shear
forces between a junction plate 11 and its wire pair
can be transmitted by compression into the wire at
right angles to the force and then transferred to
the wire in the direction of the foirce by shear in
the welded junction of the wires. It is also
preferable to have the wires welded so that the
thickness at their crossing points is the same as
3~3~Z
32
the thickness of the wires themselves so that the
neutral axes of both wires can be in the same plane
and at the intersectins of the neutral axes of the
truss core struts. Thereafter, the thermoplastic
material from which the truss element is formed
could be melted so that it could be squeezed about
the wires or alternatively, the wires could be
secured within grooves 158 and 160 by adhesive
applied over the wires or means of a separate
securing disk, shown in phantom at 168 in Figure 6
that could be bonded by adhesives or by an
electromagnetic bonding technique to the upper
surface of pad 162. In that case also, the exterior
substantially planar surface of the truss structure
would be defined by the upper surface of disk 168.
In Figure 27 still another alternative
embodiment of a truss structure according to the
present invention i5 set forth which can incorporate
additional truss members in the planes defined by
the pads on their exterior surfaces. Such members
can, for example, appear on opposite sides of the
truss structure or only on one side. The truss
structure, generally inaicated at 170, is comprised
of a plurality of connecting struts or beams 172
which terminate at pads. Those appearing on the top
surface are indicated at 174 and are arranged into
two substantially parallel rows while those
appearing on the bottom surface are indicated at 176
and lie in one row substantially parallel to the two
rows of pads 174. A grid structure comprised of
wires or rods 178 and 180 can be subsequently glued,
by epoxy or other adhexives, to the top pads 174
with wires 178 extending between the rows of pads
174. While wires 180 extend along or parallel with
the rows between adjacent pads 174. In this
~ 3~
33
particular embodiment, a single row of pads 176
forms the bottom of the truss structure and a single
wire 182 extends along the row between adjacent
pad 176.
The truss structure 170 could be comprised
of a diagonal segment cut from a truss made
according to the Figure 9 embodiment. Alter-
natively, the structure could be molded as a
separate, integral element with any desired
length. In that regard, a repeating structural unit
is shown by the dotted box 184.
With the construction set forth in Figure
27, wire 182 tie together the plurality of pads 176
appearing along the bottom surface so that they will
resist bending moments generated within the
structure. The grid formed from wires 178 and 180,
which are preferably welded together prior to their
being secured to the truss structure 170 ties
together pads 174 horizontally so that pads 174
resist downwardly and outwardly applied bending
moments. This truss structure which has been
strenythened by used of wires 178-1~2 would provide
a very unique support runner or skid device which
could be secured by any convenient means such as by
stapling or gluing it to the bottoms of containers,
pallets or other devices where it would be desirable
to have the container raised off of the floor as,
~or example, to allow the N of a forklift truck to
pass beneath the structure. It should be
understood, that other securing means besides wires
178-182 could also be employed, such as, for
example, wood strips, plastic rods, or a mesh-type
material it only being important to tie the pads
appearing in the upper and lower surface together~
It should also be understood that the strengthening
~3~
34
structure used with the truss structllre 170 could be
secured to pads 174 and 176 in any of the ways
previously discussed herein. Further, the wire
structure as shown could also be merely placed on
the truss structure with heat then being applied
locally to the pads 174 and 176 melting the material
appearing therein until it flowed about the wires at
which point heating could be stopped to allow the
material to solidify. For certain uses it might be
desirable to omit cros~-wires 180 so that the
finished structure includes only the additional
truss members 178 on the top and 182 on the
bottom~ By securing the structure to the base of
containers, the effect of having members 180 present
is achieved. Further, such structures would be
stackable for shipping purposes.
Turning now to Figures 28-31 for additional
truss panel strengthening embodiments are set forth
with each one involving a structurally sound sheet
or skin member which can be applied to one or both
sides of truss structres made according to the
present invention.
Turning first to Figures 28 and 29 the
internal truss structure is diagrammatica'ly
indicated at 190 and a portion of the structural
sheet is generally indicated at 192. It should be
understood that sheet 192 would extend in all
directions in a fashion similar to the portion shown
to produce a panel of a desired size. Sheet 192 is
preferably pressed from sheet metal or could be
molded plastic and is provided with a number of
alternating depressed and raised areas extending
below and above a common middle level. The
depressed areas are generally indicated at 194, the
raised areas are generally indicated at 196 while
the intermediate level areas are generally indicated
at 198. It will be noted that the intermediate
areas 198 fall so that they can be aligned with the
contact pads 200 of the truss structure 190. As is
shown by the shading in Figure 28 the shaped sheet
192 slopes continuously from the bottom of recessed
areas 194 up to the top surface of raised areas 196
thus producing a recessed and crossed rib structure
or a channelized structure that resists bending and
shear forces very well. The upper surface of pads
200 lie against the bottom surface of intermediate
areas 198 and can be secured thereto by any
convenient means as referred to before such as
welding, electromagnetic bonding or by use of
mechanical means such as rivets or screws. It
should also be pointed out, that the axis of struts
202 intersect the neutral axis of structural sheet
192 which is positioned centrally within
intermediate areas 198.
Turning our attention next to Figure 30 the
truss structure which can be, for example similar to
that shown in Figure 9, is sanldwiched between two
corrugated panels 204 and 206 ~with each of the
corrugated sheet members 204 and 206 being
respectively comprised of an inner sheet 208 and
210, respectively, an exterior sheet, 212 and 214,
respectively. Sandwiched between each of the inner
and outer sheets is a corrugated member 216 and 218,
respectively. The inner and outer sheets in the
corrugated panels can be comprised of a variety of
materials for instance cArdboard, plastic, wood
inner and exterior sheets with a plastic or
cardboard corrugated insert, metal or other various
combinations of these materials. The two surface
35 panel structures are themselves very stiff and when
36
secured to the pad portions of the internal truss
structure by gluing, mechanical means or any other
convenient method, an extremely strong laminated
panel structure is produced. While the corrugations
are shown in Figure 30 as extending in the same
direction it shvuld be understood that the
corrugations either on the top or bottom o~ the
truss structure could be turned orthogonally with
respect to the other. Further, while only a single
truss structure is shown as being incorporated
between the two corrugated panels, it shoul~ be
understood that a plurality of truss structures
could be secured together prior to having corrugated
panels such as indicated at 204 and 206 secured to
the outer surfaces,
Turning next to Figure 31 the skin or outer
sheet 220 secured to one side of the truss indicated
at 222 is provided with support ribs 224 which
extend lengthwise along sheet 2~0 within the open V-
shaped areas on the surface of truss structure222. The presence of ribs 224 depending from the
inner surface of sheet 220 provide additional
buckling resistance when sheet 220 is secured to the
support pads on the truss structure 222 and add
further strength to the composite structure.
In addition to being able to use the truss
structures as building or construction panels for a
variety of purposes, I have found that truss
structures made accordin~ to this invention are
uniquely suited in the preparation of containers.
Such containers could be comprised with top, bottom
and side walls such truss structures together with
suitable inner and outer skins secured thereto to
define the inner and outer walls of the container.
The walls of the container could include a single
37
truss core structure or a plurality of truss core
structures with skins again secured to the outer
sides of the composite structure~ Further,
containers could be comprised of top, bottom and
side walls where the number of truss structures used
could vary throughout the container depending upon
the strength requirements of the varius walls or
other properties desired in the container itself.
Figure 32 shows an exemplary structure and
specifically the corner and side fastening arrange-
ment in order to form the truss structures together
into such a container. The container, generally
indicated at 230, can be comprised of walls of
various thicknesses. Vertical side walls are shown
at 232 while horizontal top and bottom walls are
indicated at 234. Vertical walls 232 are shown as
including two internal truss core members, with an
inner and outer skin applied thereto and horizontal
walls 234 shown are including three interal truss
core structures again with inner and outer skins
applied. It should be kept in mind that it is the
intent of the present invention to be able to
construct the vertical and horizontal walls of a
con~ainer with that number of truss structures
required to accomplish a particular end result. The
corner or joining member can be either an integral
one-piece device~ one formed in a number of one-
piece sections. Each section includes two
perpendicularly positioned, inwardly opening
channels as indicated at 236 and 238. A porti~n of
the structure extends outwardly from each closed end
of channel members 236 and 238 meeting to form the
exterior edge of the container which is indicated at
240. The edge member could also be comprised of
straight side pieces and separate corner elements or
38
alternatively two straight edge members and an
integrally molded corner piece~ The joining members
can be molded or extruded structures could be
comprised of a wide variety of materials. The truss
panels would be suitably secured within U-shaped
channels 236 and 238, preferably by adhesives,
although other joining techniques could be used as
wellO The thickness of the walls defining the legs
of ~he u-shaped channel can vary from container to
container again depending upon the strength
requirements of the container being designed.
As was indicated previously the truss
structure used according to the present invention
has a wide variety of uses and two alternatives are
set forth in Figures 33 and 34 respectively.
Turning first to Figure 33 the truss structure
generally indicated in 250 which could, for example,
be constructed similar to the portion shown in
Figure 9, has a thin glass sheet 252 secured to the
bottom pads or junction pla~es ~54 while a thin
glass sheet, such as shown at ;256, could be secured
to the upper pads or junction plates 260. Such a
structure could be provided wil:h a suitable edge or
could be cut to a proper siæe and when so
constructed would form a lightweight but extremely
strong skylight or window structure. Since the
truss structure provides a plurality of support
points ti.e. pads 254 and 260) extremely thin glass
can be used since there is no wide span across which
the glass would have to remain unsupported.
Accordingly, 1/8 inch glass could be used and yet
produce an extremely strong surface to receive
weight loads as might be occasioned by snow, ice, or
as might be required to resist wind forces. Again
it should be pointed out that the axes of the struts
39
forming truss 250 should be constructed such that
~hey intersect the n~utral plane of the glass sheet
positioned on both the upper and lower surfaces of
truss 250. This again ensures that as strong a
composite structure as possible can be produced and
minimizes the creation of any additional bending
moments when force is applied to the composite
structure.
Turning next to Figure 34 a solar collector
is indicated generally at 270 which is comprised of
a clear or transparent sheet of glass or plastic 274
secured to the upper surface of the truss whereas an
opaque sheet or skin or material 276 is secured to
the bottom surface of truss 272. In addition, side
and end structures indicated at 278 and 280 can be
applied so as to extend around the complete
periphery of the structure formed of truss 272 and
sheets 274 and 2760 By forming such a composite
structure the space therein could be subjected to
a partial so as to make the device an ideal solar
collector. Again because of the use of the truss
structure 272 it is possible to employ extremely
thin outer skins or shee~s for members 274 and 276
and because the weight of the truss structure itself
is minimized, the weight of the entire composite
structure can be kept to very low levels. A channel
member 282 can be secured adhesively or otherwise to
the exterior surface of opaque sheet 276 and can be
formed with fluid channels 284 through which water,
air or other fluids could be passed to absorb the
heat collected by sheet 276. Againr the axes of the
struts forming truss structure 272 would be angled
so that they intersect at the neutral axis of both
sheets 274 and 276 again minimizing the creation of
any bending moments when weight ur other stress is
applied to the composite structure.
In Figure 35 an alternative embodiment is
shown by which exterior sheets could be secured to
the truss panels made according to the present
invention. Struts 290 could terminate at a pad
generally indicated at 292 which could be formed
with an opening having a T-shaped cross-~ection
generally indicated at 294. With such a pad
structure it would be possible to use rivets to
secure outer members to the truss. The rivets could
be applied to the outer member by using a jig to
properly align them and in that instance, the sheet
29g with rivets in place could be simply secured to
the truss panel by fitting the sheet 298 in place
and specifically by fitting the ends of rivets 296
within the openinys 294 of pads 292. Thereafter,
the portion of the rivet extending through pad 292
would be flattened. Alternatively, rivets 296 could
be secured within pads 292 and sheets 298
subsequently spot welded or otherwise secured
thereto either prior or subsequent to the
installation of the truss panel at a desired
location.
With respect to Figures 36 - 39 another
alternative embodiment of a truss panel is set
orth. When molding truss structures according
tothe present invention it would be possible to
construct the mold so that a premade grid 300 or
portion thereof could be placed within the mold
prior to initiating the molding operation. Thus,
when the mold halves are correctly positioned
adjacent one another and the plastic material
injected therein the truss structure as generally
indicated at 302, would result with the grid 300
~1
being integrally molded thereto and be with and
secured to the contact areas or pads 304 which
appear on and define one face of the truss structure
306. The truss structure 306 may be comprised on
any moldable material including plastic or metal
such as aluminum and the grid 300 could be pre-
formed from wires, such as aluminum or steel or
plastic. Alternatively, the mold cells could be
formed so that grid 300 would be simultaneously
formed during the molding operation so that grid 300
would be comprised of the same material as the truss
structure 306 resulting in a completely integrally
formed member 302. The grid 300 could also be
comprised of a plurality of rods laid in the mold or
it could be comprised of a pre-welded mesh structure
depending upon the needs of the product being
produced.
An end view of the resulting structure
appears in Figure 37 and is shown in a form ready to
receive an outer surface member. The axes of the
strut are shown as intersection at the point where
the grid 300 is secured on one face, as at 312. On
the other face, the axes of the struts intersect
above pads 308 and at a point substantially equal to
the neutral axes of the outer surface member such as
sheet 310 in Figure 34.
If two of ~he structures were connected
together along contact areas or pads 308, as
illustrated in Figure 38, a double truss member
could be formed with grid 300 appearing on two
exterior sides. It should be noted, however, that
now the axes of the struts are angled to meet at the
surface of pads 308 so that the axes of the struts
from both truss structures meet at the center of the
composite structure. Thus, a composite truss panel
42
structure would be produced and the two members
could be welded or adhered together in any of the
ways previously discussed which includes the use of
epoxy adhesives or electromagnetic bonding
techniques. With reference to Figure 39, the truss
members shown in Figure 37 could be curved following
the molding process so as to be formed into the
curve structure shown in Figure 39. Following the
correct bending of the truss panel 302 an exterior
sheet such as shown at 310 could be secured to
contact areas or (paths or pads) 308 with the
connection of sheet 310 to the truss panel 302 again
being accomplished by adhesive materials, welding or
by mechanical means such as rivets (not shown)~
It can be seen that by the present
invention an improved integral molded truss
structure is formed which does not require the use
of rivets, bolts or other means for connecting strut
beams to surface plates, and hence, substantially
reduces the time involved for making the truss
structure~ Further, it can be appreciated that by
altering the angle of the open grooves in the male
and female members, the thickness of the truss
structure can be varied as well as the strength
thereof. The mold can be made of beryllium copper,
steel, ceramics or other suitable material or
various combinations of materials depending on the
materials used to form the truss structure.
The truss structure of the present
3~ invention can be utilized to form flat or curved
panels utilizing a minimum of material to
efficiently attain strength and rigidity~ The
panels so formed may be used for containers,
transportation vehicles, buildings and structures of
many kinds.
~35~ L%
43
While the present invention has been
described in connection with what are presently
conceived to be the most practical and preferred
embodiments, it is to be understood that this
invention is not to be limited to the disclosed
embodiments but on the contrary, is intended to
cover various modifications thereof and equivalent
arrangements included within the spirit and scope of
the appended claims, which scope is to be accorded
the broadest interpretation so as to encompass all
such equivalent structures and methods.
