Note: Descriptions are shown in the official language in which they were submitted.
CA 02611344 2007-11-21
739/45618
PATENT
INSULATING SHEET AND REFRIGERATED TRAILER COMPONENTS
FORMED FROM SAME
FIELD OF INVENTION
This invention relates to an insulating sheet and components of a refrigerated
trailer
formed from the insulating sheet
BACKGROUND OF THE INVENTION
FIG. I illustrates a prior art refrigerated trailer 20. The trailer 20
includes a body formed
from a pair of rectangular sidewalls 22, a front wall 26 and, rear doors (not
shown) which extend
upwardly from a floor structure 28, and a roof structure 30. The front wall 26
has a cooling unit
27 provided thereon in a conventional manner. The rear portion of the floor
structure 28 is
supported by a conventional rear undercarriage assembly 29. The front portion
of the floor
structure 28 has a conventional landing gear 34 secured thereunder. The roof
structure 30 and an
upper portion of each sidewall 22 is secured to a respective top rail 35 in a
conventional manner.
The floor structure 28 and a lower portion of each sidewall 22 is secured to a
respective bottom
rail 49 in a conventional manner. The top and bottom rails 35,49 are made of a
suitable material
such as aluminum. The trailer 20 can be connected to a tractor by conventional
means, such as a
fifth wheel assembly.
As shown in FIG. 2, the sidewalls 22 are formed in a conventional manner.
While one
embodiment of a prior art sidewalls 22 is shown, this is not limiting and
there are other
embodiments known in the prior art. As shown, each sidewall 22 has an inner
thin skin 43, an
outer thin skin 47, and at least one "Z" shaped post 46 therebetween. The
inner and outer skins
= 43,47 are preferably made of fiberglass and aluminum., respectively, but
can be any combination.
CA 02611344 2007-11-21
Each post 46 is integrally formed of suitable structural material, such as
aluminum or fiberglass
polyester pultrusion. The posts 46 are generally mounted between the inner and
outer skins 43,
47 of the sidewalls 22 and are spaced apart from each other along the length
of each sidewall 22.
When assembled, the inner skin 43 is spaced from the post 46 such that a
cavity is formed. A
generally L-shaped seal 69 is provided at the bottom of the cavity to separate
the sidewall 22
from the floor structure 28. A foam is poured or injected between the inner
skin 43 and the outer
skin 47 to provide a foam core 48, to complete construction of the side wall
22. With the foam
core 48 in place, the inner skin 43 is bonded to the post 46.
Each bottom rail 49 extends the length of the respective sidewall 22 and is
connected to
the sidewall 22 in a known manner. Each bottom rail 49 has a vertical portion
60 and a
horizontal portion 62 at approximately a midpoint thereof which separates the
vertical portion 60
into an upper vertical portion and a lower vertical portion. A generally Z-
shaped member 51 is
seated against the underside of the horizontal portion 62. The member 51 is
formed of extruded
aluminum and extends along the length of each bottom rail 49. Each member 51
has a horizontal
upper leg 64 which is secured to the underside of the horizontal portion 62, a
vertical
intermediate leg 66 which extends downwardly from the upper leg 64, and a
horizontal lower leg.
68 which extends inwardly toward the interior of the trailer 20 from the lower
end of the vertical
intermediate leg 66.
The floor structure 28 includes floor material 44, which may be formed of, for
example,
aluminum or wood planks, raised up off structural floor supporting beams or
crossmembers 45
by insertion of structural thermal risers 50 between the floor material 44 and
the crossmembers
45. The risers 50 generally align with the crossmembers 45. Each end of the
crossmembers 45
has an end clip 52 that is connected to the lower vertical portion of the
respective bottom rail 49
by suitable means, such as rivets or bolts. A plurality of the cross-members
45 are provided at
spaced apart locations along the bottom rail 49. Each cross-member 45 is
integrally formed from
a conventionally formed I-beam. A barrier sheet or subpan 41 is sandwiched
between the
crossmembers 45 and the floor risers 50. The space between the floor material
44 and the subpan
41 creates a cavity in which the core 25, formed from an insulating material,
such as urethane
foam, can be poured or injected to fill the cavity.
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The subpan 41 is formed of a flat sheet of material which is seated onto the
upper surface
of the horizontal lower leg 68. When the core 25 is foamed into place, the
pressure from the
foam seals the subpan 41 against the horizontal lower leg 68. Therefore, no
fastening means are
required. Fastening means can, however, be provided.
Various sheet materials have been employed as a refrigerated trailer subpans
through the
years. Early designs were steel that was heavy and rusted badly. In the 1960's
aluminum was
substituted for steel but galvanic corrosion at the steel structural floor
support was not much of
an improvement. Later, a polyester fiberglass reinforced plastic sheet (FRP)
became the Most
popular material as it could be made light weight, strong and corrosion free.
Around year 2000, a new process was created for forming a woven FRP 70 (see
FIGS. 3A
and 3B). In this new process, glass fibers were impregnated with a
thermoplastic resin. The
resin and glass fibers were simultaneously produced and then co-mingled into a
roving 71.
Multiple rovings 71 were then woven into a cloth and as a result, the glass
fibers extended in
both the X and Y directions. Heat and pressure were applied to the cloth to
melt the
thermoplastic resin fibers, fusing the glass fibers together. Cooling the hot
sheet under pressure
produced a woven FRP sheet 70 that was very strong and light weight Because
the glass fibers
are interlocked as a result of the weaving, the bundles of fibers (strand)
cannot pull out of the
consolidated sheet 70. The thermoplastic FRP sheet 70 is tough and proved to
be superior to the
polyester sheet which was brittle. Therefore, the more efficient woven
thermoplastic FRP sheet
70 became the standard in many applications. This thermoplastic FRP sheet 70
still, however,
had a basic problem. Pin holes 33 would develop in the consolidated sheet 70
at the intersection
of the rovings in the weave, see FIG. 3A. A thin FRP sheet (not shown) was
added to prevent the
pinhole problem. This made the product less cost efficient but the woven resin
sheet was still
superior to the polyester sheet. Alternatively, extra resin and fibers were
added to fill the pin
holes 33. This form of reinforcement is very strong and energy absorbing, but
it is also
expensive. In the woven thermoplastic FRP sheet 70 shown in FIGS. 3A and 3B,
the fibers
weave back and forth in the woven cloth. When the woven FRP sheet 70 is
stressed, the fibers
tend to straighten before stressing takes place. This form of reinforcement
tends to be more
flexible, but increases its energy absorption impact properties.
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CA 02611344 2007-11-21
Another prior art configuration using FRP is shown in FIGS. 4A and 413. This
configuration uses random chopped fibers 34 to form the sheet 80. The fibers
34 are completely
=
randomly place, similar to a compressed stack of hay.
Due to the ease of processing the sheet 80 and due to the fact that this is
one of the most
cost effective methods of reinforcing the resin available, reinforcements of
this type have been
very popular. Reinforcements of this type, however, tend to be less efficient
at reinforcing the
resin. The woven thermoplastic FRP sheet 70 shown in FIGS. 3A and 3B presents
several
advantages over the sheet 80 of FIGS. 4A and 4B. As a result of weaving the
reinforcing fibers,
the tear resistance and strength properties are improved over the sheet 80.
Bundles of parallel
fibers that have been locked in place by the weave work together, as opposed
to the random
chopped fibers which are oriented in all directions. However, the cost of
weaving is significant
and woven cloth has to be sized and inventoried for the application or
considerable waste will
occur.
To eliminate weaving costs, various methods of non-woven unidirectional fiber
reinforcements have been used. For example, stitching or sewing parallel
fibers eliminates
weaving, The non-woven parallel fibers in place so they can be handled like
the woven fiber
cloth. Multiple layers of the stitched fibers are layered and then stitched
together to produce a
cloth with fiber reinforcement in various directions. The stitched cloth
fibers stay in place while
they are saturatiewith a liquid resin.
The present invention provides a reinforcement sheet which overcomes the
problems
presented in the prior art and which provides additional advantages over the
prior art, such
advantages will become clear upon a reading of the attached specification in
combination with a
=
study of the drawings.
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CA 02611344 2013-12-03
SUMMARY OF THE INVENTION
Briefly, the present invention discloses a reinforced sheet which is formed
from a plurality of
tapes having unidirectional fibers. No stitching or weaving is required to
form the reinforced sheet.
The reinforced sheet is ideal for forming a subpan for a refrigerated trailer.
In one aspect, the present invention discloses a sheet for use in forming a
component of a
trailer comprising: a first tape having a plurality of unidirectional fibers
wherein the positions of said
fibers are only maintained by resin; a second tape having a plurality of
unidirectional fibers wherein
the positions of said fibers are only maintained by resin; and wherein said
first tape is positioned
over said second tape, said fibers of said first tape are angled relative to
said fibers of said second
tape, and said first tape is fused to said second tape. In yet a further
aspect, the angle between said
fibers of said first tape and said fibers of said second tape is ninety
degrees. In a further aspect, a
density of fibers in said first tape is greater than a density of fibers in
said second tape. In a further
aspect, a content of said plurality of fibers of said first tape is the same
as a content of said plurality
of fibers of said second tape. In a further aspect, said sheet is used to form
a subpan of a trailer. In
a further aspect, said sheet is used to form an outer roof sheet of a trailer.
In a further aspect, said
sheet is used to form an inner roof sheet of a trailer. In a further aspect,
said sheet is used to form
an inner skin of a trailer side wall.
In one aspect, there is provided a trailer floor structure comprising: a
plurality of floor
supporting beams; a subpan positioned over said floor supporting beams
comprising a first tape
having a plurality of unidirectional fibers wherein the positions of said
fibers are only maintained by
resin, a second tape having a plurality of unidirectional fibers wherein the
positions of said fibers are
only maintained by resin, and wherein said first tape is positioned over said
second tape, said fibers
of said first tape are angled relative to said fibers of said second tape, and
said first tape is fused to
said second tape; a plurality of risers aligned with said supporting beams and
positioned on top of
said subpan; a floor material positioned on top of said risers; and a cavity
between said floor material
and said subpan. In a further aspect, there is provided a trailer floor
structure wherein the angle
between the fibers of said first and second tapes of said subpan is ninety
degrees. In a further
aspect, there is provided a trailer floor structure wherein a density of the
fibers of the first tape of the
subpan is greater than a density of the fibers of the second tape of the
subpan. In a further aspect,
there is provided a trailer floor structure wherein a content of said
plurality of fibers of the first tape is
the same as a content of said plurality of fibers of said second tape.
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CA 02611344 2013-12-03
In yet another aspect, there is provided a trailer wall or roof comprising: an
inner skin; an
outer skin spaced from said inner skin; at least one of said inner and outer
skins comprises a first
tape having a plurality of unidirectional fibers wherein the positions of said
fibers are only maintained
by resin, a second tape having a plurality of unidirectional fibers wherein
the positions of said fibers
are only maintained by resin, and wherein said first tape is positioned over
said second tape, said
fibers of said first tape arc angled relative to said fibers of said second
tape, and said first tape is
fused to said second tape; a cavity defined by said inner and outer skins; a
post positioned within
said cavity; and insulating material within said cavity.
In yet another aspect, there is provided a trailer wall or roof, wherein the
angle between the
fibers of the first and second tapes of one of said inner and outer skins is
ninety degrees.
In yet another aspect, there is provided a trailer wall or roof, wherein a
density of the fibers of
said first tape of one of said inner and outer skins is greater than the
density of the fibers of said
second tape of one of said inner and outer skins.
In yet another aspect, there is provided a trailer wall or roof, wherein a
content of said
plurality of fibers of said first tape is the same as a content of said
plurality of fibers of said second
tape.
In yet another aspect, there is provided a trailer wall or roof, wherein each
of said inner and
outer skins comprises a first tape having a plurality of unidirectional fibers
wherein the positions of
said fibers are only maintained by resin, a second tape having a plurality of
unidirectional fibers
wherein the positions of said fibers are only maintained by resin, and wherein
said first tape is
positioned over said second tape, said fibers of said first tape are angled
relative to said fibers of
said second tape, and said first tape is fused to said second tape.
BRIEF DESCRIPTION OF THE DRAWINGS
The organization and manner of the structure and operation of the invention,
together
with further objects and advantages thereof, may best be understood by
reference to the following
description, taken in connection with the accompanying drawings, wherein like
reference numerals
identify like elements in which:
FIG. 1 is a perspective view of a refrigerated trailer of the prior art;
FIG. 2 is a perspective view of the floor and sidewall assemblies of a
refrigerated trailer of
the prior art;
FIG. 3A is an elevated view of a prior art reinforcement sheet;
FIG 3B is a cross-sectional view of the reinforcement sheet of FIG. 3A;
5A
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CA 02611344 2013-12-03
FIG. 4A is an elevated view of a prior art reinforcement sheet;
FIG. 48 is a cross-sectional view of the reinforcement sheet of FIG. 4A;
FIG. 5A is an elevated view of the reinforcement sheet of the present
invention;
FIG. 5B is a cross-sectional view of the reinforcement sheet of FIG. 5A; and
FIG. 6 is a cross-sectional view of a portion of a prior art roof and side
wall structure of a
trailer.
513
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CA 02611344 2007-11-21
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
While the invention may be susceptible to embodiment in different forms, there
is shown
in the drawings, and herein will be described in detail, a specific embodiment
with the
understanding that the present disclosure is to be considered an
exemplification of the principles
of the invention, and is not intended to limit the invention to that as
illustrated and described
=
herein.
FIGS. 5A and 5B illustrate an embodiment of the reinforcement sheet 90 of the
present
invention. As shown, the sheet 90 includes layers of reinforced thermoplastic
tapes 31, 32. The
thermoplastic tape 31 is formed of unidirectional fibers held together by a
thermoplastic resin.
The thermal plastic tape 32 is also formed of unidirectional fibers held
together by a
thermoplastic resin. The tapes 31,32 are positioned over one another and arc
consolidated to
form the reinforced sheet 90. Consolidation is accomplished by heating and
pressing the tapes
31, 32 to cause the thermoplastic resin of tape 31 to fine together with the
thermoplastic resin of
tape 32. The tape 31 can be positioned at any desired angle relative to the
tape 32 to form the
FRP sheet 90. As shown, the fibers of tape 31 are positioned in the vertical
or Y direction and
the fibers of tape 32 are Itositioned in the horizontal or X direction. Thus,
in the embodiment
shown the tapes 31 and h are perpendicular to one another such that the fibers
in tape 31 run
transverse to the fibers in tape 32. Each tape 31,32 is extremely flat and has
very uniform fiber
distribution. As the fibers are under tension when consolidated and held in
place by the
consolidating resin, when the two tapes 31,32 are layered and consolidated,
the resulting FRP
sheet 90 is extremely thin, lightweight, smooth, strong, and pin hole free.
The straight and pre-
tensioned fiber strands become rapidly stressed when the FRP sheet 90 is
flexed, making the
sheet 90 stiff. The reinforced sheet 90 is ideal for forming a subpan for use
in a refrigerated
trailer.
Several advantages are realized in forming the sheet 90 in accordance with the
present
invention. First, there is no need to weave or stitch the fibers because the
thermoplastic resin
holds the fibers in place. Therefore, problems associated with the weaving and
stitching
processes such as cost and pinhole development are eliminated. Second, fiber
placement can be
easily controlled in the X direction as well as the Y direction and,
therefore, the strength in each
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CA 02611344 2007-11-21
direction can be tailored for a specific application. For example, for a
specific subpan
application, more fibers can be provided in the major direction of the trailer
(front to back) than
in the in minor direction (side to side), without sacrificing integrity of the
resulting sheet 90.
Third, the fiber content can be varied in each direction, for example, X or Y,
independently and
will result in a sheet 90 having different directional strength properties.
The reinforced sheet 90 has been shown and described in connection with use as
a
subpan, however, other uses of the sheet 90 can be made. The reinforced sheet
90 can, for
example, be used to form the inner sIdn 43 of the side wall 22 of the trailer.
The reinforced
sheet can also be used to form portions of the roof structure 30 as shown in
FIG. 6.
The roof structure includes an inner roof sheet or skin 92, an outer roof
sheet or skin 91
spaced from the inner roof sheet, and at least one "Z" shaped post 93
therebetween. The posts 93
are generally mounted between the outer and inner skins 91,92 and are spaced
apart from each
other along the length of the roof 30. When assembled, the inner roof sheet 92
is spaced from the
post 93.
The top rail 35 is formed from a first vertical wall 72, a second wall 73
which is
perpendicular to the first vertical wall 72, a third wall 74 which is
perpendicular to the second
wall 73 and parallel to the to the first wall 72, and a fourth wall 75 which
is perpendicular to the
third wall 74 and parallel to the second wall 73. The second wall 73 extends
inwardly toward the
interior of the hailer. A flange extends inwardly from the third wall 74
toward the interior of the
trailer. The flange is perpendicular to the third wall 74. The fourth wall 75
extends outwardly
from the interim' of the trailer. The fourth wall 75 has a plurality of spaced
apart apertures
provided therethrough for acceptance of rivets which pass through the roof
structure 30.
. The top rail 35 provides connection between the side wall 22 of
the trailer and the roof
structure 30. An upper portion of the outer skin 47 of the side wall 22 abuts
the inner surface of
the first wall 72 of the top rail 35. A portion of the lower surface of the
outer roof sheet 91 abuts
the upper surface of the fourth wall 75 of the top rail 35. A comer rail 94
extends from the inner
skin 43 of the side wall 22 to the inner roof sheet 91 of the roof structure
30. A cavity is defined
by the outer and inner skins 91, 92 of the roof structure, the inner and outer
skins 43,47 of the
side wall 22, the side rail 35 and the corner rail 94 and foam is poured or
injected in the cavity.
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CA 02611344 2013-12-03
The reinforced sheet 90 can be used to form the outer roof sheet 91 or the
inner roof sheet
93. Alternatively, the reinforced sheet 90 can be used to form the outer and
inner roof sheets 91, 93.
Finally, it is to be understood that sheet 90 can include any number of layers
31, 32 desired
and is not limited to a sheet including two layers as shown in FIGS. 5A and
5B.
8
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