Note: Descriptions are shown in the official language in which they were submitted.
LIGHTWEIGHT CEMENTITIOUS PANEL POSSESSING HIGH DURABILITY
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is an International Application of U.S. Serial No.
14/028,009
filed September 16, 2013, U.S. Serial No. 14/028,055 filed September 16, 2013,
U.S. Serial No.
14/028,089 filed September 16, 2013, and U.S. Serial No. 14/028,072 filed
September 16, 2013.
BACKGROUND
100011 Cementitious panel is one type of material used in the construction of
buildings. One
disadvantage to commonly used cementitious panel is that such panel possesses
a high density
and weight due to material composition. Commonly used cementitious panel is
difficult to
manage and use in the construction process due to its great weight per square
foot. For example,
standard cementitious board is approximately twice the weight per square foot
of gypsum board.
100021 Moreover, cementitious board used in the construction process may
require a low
permeability to increase the longevity of installation. Any introduction of
additional ingredients
to the composition of cementitious board may decrease durability such that the
cementitious
board does not pass required structural certification for use in construction.
[0003] The present invention relates to a cementitious panel comprised of a
low density core
surrounded by upper and lower facers of reinforcements embedded into the core
or attached to it
using cementitious slurry or adhesives. The core, the slurry or both can be
made and/or enhanced
with a low permeability to water (or water vapor) characteristic by adding
ingredients to their
respective compositions to achieve permeability values similar to or below
those of type- 15
bitumen treated felt paper.
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[0004] More particularly, the present invention relates to panels or boards
whose opposed broad
faces are reinforced by a network of fibers which may be adhered at a surface
thereof e.g. be
adhered to or embedded at or just below the cementitious surfaces thereof and
include a low
density core using a light weight aggregate surrounded by cement paste to fuse
the lightweight
aggregate together. Still more particularly, the present invention relates to
a cementitious board
[0005] whose longitudinal edges are reinforced by a network of fibers. Such a
cementitious
panel or board may, for example, be a light-weight concrete panel, a tile
backerboard panel, or
the like.
[0006] The word "cementitious" as used herein is to be understood as referring
to any material,
substance or composition containing or derived from a hydraulic binder such as
for example,
Portland cement (see below), aluminate cement, and/or a pozzolan such as for
example fly ash or
blast furnace slag. The term "slurry" is to be understood as referring to a
flowable mixture, e.g. a
flowable mixture of water and one or more hydraulic binders and if desired or
necessary,
additional additives such as rheology modifiers, water reducers, chemical set
control admixtures,
and the like. The term "core" is to be understood as referring to a mixture of
a hydraulic binders,
water and aggregate (such as sand, expanded shale or clay, expanded
polystyrene beads, slag and
similar materials¨see below), as well as, if desired or necessary, additional
additives such as
foaming agents, rheology modifiers, water reducers, and the like.
[0007] The term "slurry pervious reinforcing mesh" is to be understood as
characterizing a mesh
as being suitable for use in the preparation of a concrete panel by having
openings sufficiently
large to permit penetration of a cementitious slurry or a slurry component of
a core mix, or a full
core mix, into and through the openings so as to permit (mechanical) bonding
of the mesh to the
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core either by for example by being cemented to the core or by being embedded
in a face or
surface of the core of a panel.
[0008] The expression ''slurry impervious mesh" is to be understood as
characterizing a mesh as
being water impervious or as being able to filter out or inhibit the
penetration of slurry or core
solids therein so as to inhibit (mechanical) bonding of the mesh to the core
by the cementitious
material.
[0009] It is to be understood herein that the expression "adhered to" in
relation to a reinforcing
mesh component (e.g. mesh, mat, fabric, tissue, etc.) means that the mesh
component may be
adhered for example to a face or surface by any suitable means such as by an
adhesive, by a
binder, by a slurry, by a core, or by being embedded in, at or immediately
beneath the surface of
a respective face or surface such that the mesh component is effectively
bonded to the core, i.e. a
hardened or set cementitious material extends through the interstices of the
fibrous layers.
[0010] Keeping the above immediate definition in mind, it is to be understood
herein that the
expression "adhered to said core at" in relation to a reinforcing mesh
component (e.g. mesh, mat,
fabric, tissue, etc.) means that the mesh component does not extend beyond the
specified face,
area, region, or the like, i.e. it is restricted to the specified face region
etc. Thus for example in
relation to a broad face reinforcing mesh indicated as being adhered to a core
at a broad face
means that the mesh is restricted to being adhered to the broad face.
[0011] The word "woven" as used herein is to be understood as characterizing a
material such as
a reinforcing fabric (e.g., mesh, tissue or the like) as comprising fibers or
filaments which are
oriented; oriented fibers or filaments being disposed in an organized fashion.
[0012] The word "non-woven" as used herein is to be understood as
characterizing a material
such as a reinforcing fabric (e.g. mat, tissue or the like) as comprising
fibers or filaments which
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are oriented (as described above) or which are non-oriented; non-oriented
fibers or filaments
being disposed in random fashion.
[0013] In general, a reinforced cementitious panel or board may be fastened,
or sometimes
adhered, to a wall, or a wall frame, for the construction of a wall and
particularly for the
construction of a wall where high moisture conditions are to be encountered.
Such a wall panel
may provide a long lasting substrate for humid or wet areas such as shower
rooms and bath
rooms and provide high impact resistance where there is high number of people
circulating.
Exterior installations are also encountered. For example, such a reinforced
cementitious panel or
board may be used as a substrate for ceramic tile in bath rooms, shower rooms,
locker rooms,
swimming pool rooms and other areas where the wall are subject to frequent
splashing of water
and high humidity. For exterior installations, such a reinforced cementitious
panel or board may
be used as a substrate for a stucco wall system or a masonry veneer wall
system. Once the panel
is affixed to a wall frame a wall facing material may, as desired or
necessary, in turn be affixed
thereto such as, for example, ceramic tile, thin brick, thin marble panels,
stucco or the like.
Reinforced cementitious panels or boards having cores formed of a cementitious
composition
with the faces being reinforced with a layer of fabric bonded thereto are
known; see for example
U.S. Pat. No. 1,439,954, U.S. Pat. No. 3,284,980, U.S. Pat. No. 4,450,022,
U.S. Pat. No.
4,916,604, etc. Further, cementitious panels or boards with reinforced edges
are known; see for
example, U.S. Pat. No. 6,187,409.
[0014] Various processes for the preparation of such cementitious boards or
panels are also
known. British Patent application No. 2,053,779 for example discloses a method
for the
continuous production of a building board which comprises advancing a pervious
fabric on a
lower support surface, depositing a slurry of cementitious material onto the
advancing fabric,
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contacting the exposed face of the slurry with a second fabric such that the
slurry penetrates
through the fabric to form a thin, continuous film on the outer faces of the
fabric.
[0015] Because of its cementitious nature, a cement board may have a tendency
to be relatively
brittle.
[0016] Cementitious wall board or panels are often attached at their marginal
edges to the
building framework with for example fasteners such as nails, screws and the
like. When
fasteners for example such as screws or nails are installed near the edge
(less than 1/2), it is
highly desirable that the edge be able to retain sufficient structural
integrity such that the panel
remains attached to a wall member, i.e. that the panel have a relatively high
fastener pull
resistance such that the fastener will not laterally pull through or break
through the board edge
easily.
[0017] It is known to augment the strength of the border edge regions by
wrapping the fabric
covering one broad face of the board around the edge so as to overlay the
fabric on the other
opposite broad side thereof
[0018] U.S. Pat. No. 4,916,004, for example, discloses a cement board having a
woven mesh of
glass fibers immediately below each face thereof, the mesh in one broad face
continuing under
the surface of both longitudinal edge faces, with the two meshes in an
abutting or an overlapping
relation along the longitudinal margins of the opposite face. Please also see
U.S. Pat.
Nos. 5,221,386 and 5,350,554.
[0019] U.S. Pat. No. 4,504,533, for example, discloses a gypsum board in which
a composite
web of a non-woven fiberglass felt and a woven fiberglass mat covers the upper
and lower faces
of a gypsum core while only the lower non-woven fiberglass felt is wrapped
around the
longitudinal edges of the gypsum core so that the non-woven fiberglass felt
extends partially
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inward on the upper face of the core such that the border edge regions are
covered only by non-
woven fiberglass felt.
[0020] U.S. Pat. No. 1,787,163 on the other hand discloses a gypsum board in
which side edge
portions include a separate strip of U-shaped fabric extending from one broad
face across the
edge to the other broad face; the fabric legs of this separate strip each
extend into the plaster core
body beneath a respective sheet of fibrous material covering a respective
broad face, i.e. the legs
are submerged below the broad face and in particular below the broad face
reinforcement means.
[0021] It would be advantageous to be able to have an alternate manner of
making an alternative
type panel configured such that when a nail, screw or like shaft fastener is
inserted close to the
edge of a panel the mesh reinforced edge may minimize edge break out by the
nail or screw or
like shaft fastener of edge and thus provide secure attachment of the panel to
a framing support.
[0022] It would for example be advantageous to be able to customize the
reinforcement
characteristics of the longitudinal edge area of a panel by being able to
choose a desired
reinforcement mesh component which is different from the mesh used for the
broad faces of a
wall panel core and being able to choose a desired attachment technique to the
longitudinal edge.
It would be advantageous for example too be able to have a panel or board
wherein the edge
reinforcing mesh may be different from the broad face reinforcing mesh (e.g.
of a different
substance, of different mesh openings, of non-oriented fibers or filaments
rather than oriented
fibers or filaments).
[0023] It would be advantageous to be able to have a panel wherein the
longitudinal edge face of
the panel may be more or less free of cementitious material so as to allow the
longitudinal edge
face to be used as a support substrate for a visual indicia such as color,
images, symbols, words,
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etc., i.e. such that an indicia would not be covered up during the
manufacturing process by
cementitious material.
100241 It would be advantageous to be able to have a means of treating, the
side edges of the
board in the course of manufacture in such a manner as to enhance its
structural qualities and its
use for the purposes intended. It in particular would be advantageous to be
able to have a means
of manufacturing the edges of the board in such a manner that it will have
impact resistant edges
and be able to be constructed so as to be able to offer a relatively higher
lateral fastener pull
resistance in the edge area than in the central core area or than a board not
having such
reinforced edges.
[0025] It would be advantageous to change the recipe for cementitious board to
include at least
one lightweight aggregate as to decrease the overall weight and density of the
board while
maintaining low permeability.
SUMMARY
[0026] In at least one embodiment of the present disclosure, a lightweight
cementitious panel
formed from a core mix comprises one or more lightweight aggregate filler in
the amount of 0.5
to 5 weight percent of the core mix, one or more binders in the amount of 35
to 75 weight
percent of the core mix, rheological admixture in the amount of about 0.5 to 5
weight percent of
the core mix, surfactant in the amount of 0 to 0.1 weight percent of the core
mix, one or more
normal weight aggregate filler in the amount of 5 to 50 weight percent of the
core mix, and water
in the amount of 5 to 20 weight percent of the core mix.
[0027] In at least one embodiment of the present disclosure, a lightweight
cementitious panel
comprises a low density core comprising one or more lightweight aggregate
filler in the amount
of 0.5 to 5 percent of the low density core, one or more binders in the amount
of 35 to 75 weight
percent of the low density core, rheological admixture in the amount of about
0.5 to 5 weight
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percent of the low density core, surfactant in the amount of 0 to 0.1 weight
percent of the low
density core, one or more normal weight aggregate filler in the amount of 5 to
50 percent of the
low density core, and water in the amount of 5 to 20 weight percent of the low
density core. In
such an embodiment, the lightweight cementitious panel also comprises a
plurality of reinforcing
mesh overlying the faces of the low density core, at least the first
reinforcing mesh being covered
with a cementitious slurry.
100281 In at least one embodiment of the present disclosure, a lightweight and
high durability
cementitious panel comprises a high durability and low density core, the core
comprising a first
plurality of expanded polystyrene beads having an expanded diameter of 0.060
inches to 0.130
inches, and a second plurality of expanded polystyrene beads having an
expanded diameter of
0.030 inches to 0.125 inches.
BRIEF DESCRIPTION OF THE DRAWINGS
100291 Embodiments of the invention will now be described by way of example
with reference
to the accompanying drawings.
[0030] FIGS. 1 to 4 illustrate in schematic cross sectional views steps in the
formation of an
example panel in accordance with the present invention;
[00311 FIG. 5 is a schematic partial cross sectional view of a reinforced edge
of a panel made in
accordance with the steps illustrated in FIGS. 1 to 4;
100321 FIG. 6 is a schematic partial cross sectional view of a reinforced edge
of another example
panel made in accordance with the present invention wherein only one broad
side face includes
reinforcing mesh at the marginal edge area thereof
[00331 FIGS. 7 to 11 illustrate in schematic cross sectional views steps in
the formation of
another example panel in accordance with the present invention having a U-
shaped edge
reinforcing mesh;
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[0034] FIG. 12 is a schematic partial cross sectional view of a reinforced
edge of a panel made
in accordance with the steps illustrated in FIGS. 7 to 11;
[0035] FIG. 12a is a schematic partial cross sectional view of a reinforced
edge of a panel
wherein the panel includes light weight aggregates of expanded closed-cell
polystyrene beads;
[0036] FIG. 12b is a schematic panel cross sectional view of a reinforced edge
of a panel
wherein the panel includes light weight aggregates of small-diameter expanded
closed-cell
polystyrene beads and large-diameter expanded closed-cell polystyrene beads;
[0037] FIGS, 13 and 13a each illustrate in schematic partial cross sectional
view a step in the
formation of additional example panels in accordance with the present
invention wherein the
bridging member is not adhered to the core;
[0038] FIGS. 14 and 14a are each schematic partial cross sectional views of a
reinforced edge of
a panel made in accordance with a process respectively including the step
illustrated in FIGS. 14
and 14a;
[0039] FIG. 15 is a schematic partial cross sectional view of the edge of
another example panel
in accordance with the present invention;
[0040] FIG. 16 is a schematic partial cross sectional view of the edge of a
further example panel
in accordance with the present invention;
[0041] FIG. 17 is a schematic partial cross sectional view of the edge of yet
another example
panel in accordance with the present invention;
[0042] FIG. 18 is a partial schematic perspective view of the forward end of
an apparatus in
accordance with the present invention for making an edge reinforced panel in
accordance with
the present invention;
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[0043] FIG. 19 is a partial schematic perspective view of the central part of
the example apparatus
for which the forward end is shown in FIG. 18;
[0044] FIG. 19a is a schematic enlarged side view of the crank system for a
support member of
the first mesh layer alignment component shown in FIG. 19 and which includes
dual crank
components;
[0045] FIG. 19b is a schematic enlarged top view of the crank system shown in
FIG. 19a;
[0046] FIG. 19c is a schematic enlarged end view of the crank system shown in
FIG. 19a;
[0047] FIG. 19d is a schematic enlarged view of the roller and accompanying
forming wire to be
used with the system shown in FIG_ 19;
[0048] FIG. 19e is a schematic enlarged view of the roller and accompanying
rotating rod to be
used with the system shown in FIG. 19;
[0049] FIG. 20 is a partial schematic perspective view of the rear end of the
example apparatus for
which the forward end is shown in FIG. 18;
[0050] FIG. 21 is a partial schematic perspective view of the forward end of
an apparatus in
accordance with the present invention for making an edge reinforced panel in
accordance with the
present invention wherein the bridging member is not adhered to the core;
[0051] FIG. 22 is a partial schematic perspective view of an example strip
feeding mechanism for
feeding reinforcing strips to the forward end illustrated in FIG. 18;
[0052] FIG. 23 illustrates in schematic perspective view an edge strength test
for a panel section
having an edge reinforcement in accordance with the present invention and a
panel section having
a known wrap around reinforced edge as illustrated in U.S. Pat. No. 5,221,386
(see FIG. 6 of this
patent).
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[0053] The invention will hereinafter be described in more detail in relation
to the drawings by
way of example only, in terms of a panel (e.g. wallboard) having a
cementitious core comprising
a hydraulic cement and aggregate of a lightweight type. The drawings are
schematic in nature,
are not drawn to scale and in some cases elements are exaggerated for purpose
of illustration
only.
DETAILED DESCRIPTION
100541 In at least one embodiment of the present disclosure, the first and
second edge strip
members of a U-shaped edge reinforcing mesh may be adhered to a cementitious
board core at
respective marginal areas of a respective longitudinal marginal edge by being
cemented thereto
or as desired by being embedded in respective broad faces. A bridging member
may as desired
also be cemented to or as desired be embedded in a respective longitudinal
edge face. On the
other hand a bridging member need not if desired be adhered to a respective
longitudinal edge
face but may merely abut such face or as desired be spaced apart therefrom; in
this latter case the
bridging member may be water impervious such that, for example, cementitious
material may
not pass into or through the bridging member during the manufacture of a panel
such that it is
possible to for example provide the exposed side of the bridging member with a
desired indicia
as described above.
[0055] A cementitious board or panel of the present invention may be designed
to be used as a
backerboard for tile, thin brick, thin stones, architectural stone veneer,
synthetic or natural
stucco, paint, exterior insulation and finish systems or other finishes that
can be applied onto
concrete. It may be of interior or exterior grade and can be used in such
places as kitchens, bath
room, shower room, corridors, exterior wall, or any places that require water
resistance and
impact resistance. It may be used to construct fire resistant partition walls.
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[0056] As may be understood, in accordance with the present invention a
cementitious panel
may have a composite or sandwich like construction wherein a cementitious core
is bounded on
each of its two major or broad faces by a respective reinforcing mesh or mat
component of
fibrous material; each reinforcing mesh or mat component being adhered to the
panel core at a
respective major face thereof.
[0057] The longitudinal edge faces of a panel may also be covered or closed
off by an edge
reinforcing mesh or mat component. The edge reinforcing mesh or mat component
may be
adhered to the longitudinal edge face, merely about the longitudinal edge face
or be spaced apart
from the longitudinal face; this type of reinforcing mesh or mat component
may, for example
take on a U-shaped configuration as discussed herein. Alternatively, if
desired, the longitudinal
edge face or a part thereof may be open, i.e. not covered by a reinforcing
mesh or mat material.
In this latter case one or both of the marginal areas adjacent a longitudinal
edge on opposite
broad faces may be provided with an edge reinforcing member.
[0058] A panel in accordance with the present invention may have a
longitudinal edge face
which may be more or less free of cementitious material so as to allow the
longitudinal edge face
to be used as a support substrate for a visual indicia such as color, images,
symbols, words, etc.,
i.e. the reinforcing mesh or mat may be configured such that an indicia
support area would not be
covered up during the manufacturing process by cementitious material.
[0059] The reinforcing mesh or mat components or members thereof whether for a
broad or
major face or for a longitudinal edge face may take the form of a woven or non-
woven fabric or
mesh such as a woven mesh or scrim, a non-woven mesh, a non-woven pervious
mesh or mat,
etc. Suitable fiber filaments may be formed into a woven material by the
employment of a
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suitable method such as knitting or weaving. Suitable fiber filaments may be
formed into non-
woven material by the employment of a suitable method such as gluing or
fusion.
[0060] The reinforcing mesh for a broad face may for example take the form of
a woven mesh
or a non-woven oriented mesh or mat. On the other hand a mesh for a
longitudinal edge face
may take the form of a non-woven mesh or mat, in particular a non-woven non-
oriented mesh or
mat.
[0061] A woven mesh or mat for a broad face may for example be composed of
glass fibers and
be in the form of woven or knitted fabric or scrim. When a glass fiber network
is used in
conjunction with an alkaline cementitious material, for example, a highly
alkaline Portland
cementitious composition, the glass fibers may be made from an alkaline
resistant glass or have a
protective coating so that damage which might result from reaction with the
alkaline
cementitious material, may be minimized or avoided; this may be accomplished
by coating the
fibers with an alkali resistant coating such as an epoxy or plastisol resin.
The teinforcing mesh
may, for example, be a fiber-glass scrim, in particular, a woven mesh of vinyl
(e.g. polyvinylchlori de) coated glass-fiber yarns.
[0062] The reinforcing mesh for a broad face may, if desired, alternatively,
be in the form of a
non-woven oriented fabric or web, bonded with a suitable synthetic resin or by
heat. The mesh
may be of non-woven oriented glass fiber tissue. A non-woven glass fiber
tissue may be of
resin-bonded fibers or filaments, for example fibers bonded with or without
urea-formaldehyde
and may have a weight of about 2 to 4 oz. per square yard. The fibers may for
example have a
diameter of 10 to 20 urn.
[0063] However, a woven or non-woven oriented mesh of other materials may be
used for
reinforcing a broad face of a panel. Such a mesh may for example be of an
inorganic material
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such as for example, of a metal (e.g. a steel fiber), of asbestos, of alumina,
of zirconia, of carbon
and the like. Alternatively, a mesh may be of synthetic material such as for
example of organic
polymeric fibers, for example, nylon fibers, polyvinylidene chloride fibers,
polyester fiber yarns
coated with PVC, aramid resin fibers (e.g. as sold under the trademark
Kevlar), polyolefin fiber,
e.g. polyethylene or polypropylene; of fluorinated polyolefin, e.g.
polyvinylidene fluoride or
polytetrafluoroethylene; or polyamide fiber; or of polyester fiber, e.g.
poly(ethylene
terephthalate); or of cellulosic fiber and the like.
[0064] The mesh size and the fiber diameter for a woven or non-woven oriented
mesh used to
reinforce the broad or major faces of the core may be selected according to
the strength desired
in the board and the size of the aggregate in the concrete mix. A mesh for a
broad face
reinforcement may, for example, have a relatively loose thread or mesh count
per inch (warp
xfill) such as for example, of from 4x4 to 18x18, of 10x8, etc. for most
purposes.
[0065] In accordance with the present invention the reinforcement of the edges
and margins of a
cementitious board or panel may be accomplished by using a separate type of
woven or non-
woven mesh or mat fabric as compared with the reinforcing mesh used for the
broad faces;
advantageously, the reinforcing mesh for the edge face may be a non-woven non-
oriented mesh.
For example, a reinforcing mesh for the longitudinal edges may have relatively
tight intercises as
compared with a reinforcing mesh for a broad faces-2 to 4 oz. per sq, yd.¨;
the relatively tight
intercises makes attachment of the board to a wall framework with nails or
screws more secure,
due to of a greater amount of mesh material per unit area than is present for
the central portion of
the major or broad faces of the panel.
[0066] The fibers in a non-woven mesh or mat for reinforcing a longitudinal
marginal edge may
be either randomly distributed or orientated. In the first case the
longitudinal edges of the board
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will have substantially the same breaking strength in the longitudinal and the
transverse
directions. In the latter case, the longitudinal edges of the board can have
high strength in the
transverse direction but a lower strength in the longitudinal direction or
vice versa. Thus, by
varying the tissue characteristics, the edges may be made stronger in a
particular direction, or
additional strength can be provided in desired locations, e.g. along the board
edges, by using
tissues of appropriate fiber distribution.
[0067] The mesh size and the fiber diameter for a non-woven oriented mesh used
to reinforce
the longitudinal marginal edge face adjacent the longitudinal edge face may
also be selected
according to the strength desired in the longitudinal edge. However, a mesh
for a longitudinal
edge margin face may for example have a tighter weave or intercices than is
used for the broad
faces, i.e. for example a thread or mesh count tighter than 10x8. Thus the
reinforcing meshes for
the marginal edge faces may have relatively small openings such as for example
meshes with a
16x10 count per inch may be used so as to secure the desired or necessary
penetration of the
fabric along the edge margins with the cementitious composition.
[0068] The nonwoven mesh for reinforcing a longitudinal marginal edge may for
example
comprise fleece-like mats or felts of fibers arranged in a non-oriented
manner. The nonwoven
non oriented mesh reinforcing material may be three dimensional in nature with
the fibers
thereof defining interconnecting voids. In general, the non-oriented mesh
which may be
employed in the reinforcement of the longitudinal marginal edges are generally
those in which
the voids are relatively small in size, i.e. the fibers in the mesh, mat or
felt are relatively tightly
packed, e.g. of 2 to 4 oz. Per square yard.
[0069] A mesh for reinforcing a longitudinal marginal edge may be of a
material as described
above for the mesh for reinforcing the broad face of a panel. Such a mesh may,
for example be
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of a synthetic material (i.e. polymer) such as described above; it may in
particular be of
polypropylene or of a polyester. The fibers in the non-woven mesh, may be held
in place by
needle punching or, in the case of fibers derived from synthetic material such
as an above
describe polymer, by melt bonding or gluing (with a suitable adhesive) of the
individual fibers to
each other at points of intersection.
[0070] Illustrative of the non-woven spatial fabrics which can be employed in
preparing the
structures of the invention is a non-woven mat which is described herein
below;
[0071] If desired the mat may be a mixture of two or more different types of
fiber, or two or
more mats of different fibrous material may be used.
[0072] The fibers in the mat may be multi-filament or monofilament.
[0073] It is preferred to use meshes that are flexible, and for this reason it
is preferred to use
relatively thin mats having a maximum thickness of the order of about 0.5 mm
to 1 mm (e.g. up
to 0.2 mm) and to use meshes made of relatively thin fibers, e.g. having a
fiber diameter of no
more than 1 mm in particular no more than 0.2 mm (i.e. 200 microns).
[0074] A reinforcing mesh whether for the broad faces or for the longitudinal
marginal edges
may be bonded to the core in any suitable fashion keeping in mind the
reinforcing role that these
meshes are to play. A reinforcing mesh may for example be bonded to a core by
a cementitious
slurry, for example, a portland cement slurry, or may be bonded by a
cementitious component of
a core mix extending through the openings in the mesh.
[0075] In accordance with the present invention a longitudinal edge face of a
longitudinal
marginal edge (i.e. a minor side face of a panel) need not be reinforced with
or be covered with a
reinforcing fabric. If, for example, a longitudinal edge margin is reinforced
with a U-shaped
reinforcement mesh component the bridge member thereof need not, if so
desired, be adhered to
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the longitudinal edge face; on the other hand the bridge member may, if
desired, be adhered to a
longitudinal face as, for example, by an adhesive, by cementing or by being
embedded in the
core surface cement material. As may be appreciated from the above a bridge
member links or
connects a pair of arm members (i.e. edge strip members). These arm members
are adhered to a
marginal area of a respective broad face. However, such adherence need not be
over the entire
lateral width thereof. For example, a marginal area may comprise a grip region
and an adhesion
free region. The adhesion free region may border the longitudinal edge face.
In this latter case
an arm member may be adhered only to the grip region and not to the adhesion
free region such
that the cross section of the marginal edge may show that a U-shape surface
including the surface
of the longitudinal edge is not adhered to the U-shaped reinforcement mesh
component, distal
end portions only of the arm members are adhered to the marginal edge faces.
Keeping in mind
that the purpose of the U-shaped reinforcement mesh component is to reinforce
the longitudinal
edge of a panel the lateral width of a grip region is preferably larger (e.g.
substantially larger) the
lateral width of an adhesion free region bordering the longitudinal edge face.
[0076] The reinforcing mesh of the major faces and a mesh disposed about a
longitudinal
marginal edge faces may, for example, be held in place in the set product by
allowing a
cementitious composition to infiltrate intercices of such a mesh such that at
least some of the
fibers of the mesh may be embedded in the hardened cementitious composition.
In this case in
order to facilitate such penetration of a mesh by the cementitious
composition, the fabrics should
comprise a sufficient or desired degree of voidage so as to allow the
unhardened cement
composition to penetrate the mesh. In other words, a reinforcing mesh adhered
to a broad face of
a core and at least the portion of an edge reinforcing mesh adhered to a core
along a marginal
area thereof may be pervious meshes (i.e. pervious to cementitious slurry);
the openings in a
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mesh, scrim or other fabric in this case are to be sufficiently large to
permit passage of the mesh
bonding material such as a Portland cement slurry, i.e. such that a mesh or
scrim is cemented to
or embedded in a face or surface.
[0077] In accordance with the present invention a cementitious panel may be
produced
employing a core mix alone or if desired by also employing a cementitious
slurry.
[0078] By way of example only, a cementitious panel in accordance with the
present invention,
may be obtained by following the immediately herein below described steps. A
first web of
reinforcing mesh may first be provided for a core face which during
manufacture forms part of
the bottom layer of the panel and which is not as wide as the panel width. A
marginal section or
area of the first web on each side of the center may be disposed to overlap a
portion of an edge
reinforcing web or mesh of fabric leaving outer edge portions thereof
uncovered thereby; the
uncovered portion may be folded over to wrap each of the two edges of the core
layer and also to
extend over on to the top face of the core layer and overlap the upper broad
face reinforcement
mesh. A cementitious slurry may first be applied onto the first web so as to
embed it therein and
may be applied so as to leave uncovered at least an outer portion of the edge
reinforcing webs for
covering the longitudinally edge faces. The cementitious slurry may also be
applied as to leave
uncovered at least a center portion of the first web. The center section of
the first web receives
the core layer after the application of the slurry if used and it also may be
laid down so as to
leave exposed outer marginal portions of the web or mesh to be wrapped about
the longitudinal
edges. A second web of reinforcing fabric (which forms the top layer of the
panel) which is
preferably of the same width as the first web may be laid down on top of the
core layer so as to
overlay it and as desired or necessary is pushed just under the upper surface
of the core so as to
be embedded in the top surface. Bonding material such as a Portland cement
slurry may also as
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desired or necessary is applied to the second web either before or after it is
laid down on the core
layer. The core layer may also act as a bonding material instead of a slurry,
for the first web
and/or the second web.
[0079] A cementitious slurry may for example comprise water and a cementitious
material
(i.e. a hydraulic cement as described above). A cementitious slurry, such as a
Portland cement
slurry, is strongly basic or alkaline having a pH of at least 11, due to the
presence of calcium
hydroxide, e.g. a pH of from 11 to 14, such as a pH of 11 to 13, e.g. a pH of
12.5 to 13. Such a
slurry tends to react with, or have an affinity for, base-reactive surfaces
and consequently have a
decided tendency to cling, bindor react to these surfaces.
[0080] A core mix may for example comprise water, a cementitious material or
binder (i.e. a
hydraulic cement which is able to set on hydration such as for example,
Portland cement,
magnesia cement, alumina cement, a pozzolan such as fly ash or blast furnace
slag, gypsum, and
the like or a blend thereof), a normal weight aggregate, a lightweight
aggregate, a chemical set
admixtures, a rheological admixture, and one or more surfactants.
[0081] In at least one embodiment of the present disclosure, the normal weight
aggregate within
the core mix may be of a single use or a combination use of sand, stone,
crushed stone,
limestone, shale, clay, recycled concrete, granite or other minerals. In a
preferred embodiment,
the normal weight aggregate is composed of mortar grade sand. The particle
size distribution of
the normal weight aggregate may vary over a wide range e.g. up to about 'A
(e.g. up 1/4) of the
thickness of the panel or smaller, such as for example from {fraction (1/32)}
of an inch to 1/4 of
an inch.
[0082] In at least one embodiment of the present disclosure, the core mix is
composed so as to
comprise a chemical set control admixtures acting as a retarder or
accelerator. In such an
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embodiment, the chemical set control admixtures may include, but are not
limited to, lithium
salts such as lithium carbonate, sodium tripolyphostate, Triethanolamine
(TEA), calcium nitrite,
sodium nitrite, calcium formiate, aluminum sulfate, sodium carbonate, calcium
chloride,
magnesium fluorosilicate, sodium sulfate, sodium silicate, calcium hydroxide,
calcium-aluminate
cement, calcium sulfate, calcium hydroxide, calcium nitrite, boric acid,
borax, formic acid, citric
acid, sodium citrate, sodium gluconate, glucose, sucrose, and fructose.
[0083] In at least one embodiment of the present disclosure, the core mix is
composed so as to
comprise a lightweight mineral and/or non-mineral (e.g. organic) aggregate(s)
(e.g. sand,
expanded clay, expanded shale, expanded perlite, expanded vermiculite,
expanded pumice,
bottom ash, fly ash, expanded closed-cell glass beads, closed-cell polystyrene
beads (expanded
or not), polyurethane, blast furnace slag, ceramic hollow sphere, glass hollow
sphere, plastic
hollow sphere, geopolymer hollow sphere, fly ash hollow sphere, silicate
hollow sphere and/or
the like). Suitable lightweight aggregates, may for example in particular be
cellular in nature; a
suitable non-mineral lightweight aggregate is for example expanded closed-cell
polystyrene
beads.
[0084] Aggregate for use in the cementitious core mix composition may be
selected in
accordance with the desired density of the finished panel. Aggregate may, for
example, have a
density of up to 120 pounds per cubic foot. For example, lightweight
aggregates such as
obtained from expanded forms of slag, clay, shale, slate, perlite,
vermericulite and the like may
produce panels having a density of from about 80 to about 115 pounds per cubic
foot. On the
other hand a material such as closed-cell glass beads or a plastic such as
polystyrene beads may
be used to obtain a panel having a density of from about 40 to 70 pounds per
cubic foot or lower.
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[0085] In at least one embodiment of the present disclosure, the core mix may
contain
rheological admixtures for water reduction or rheology modification. In such
an embodiment,
these rheological admixtures may be of a single use or a combination use of
melamine sulfonate,
sodium naphthalene sulfonate, lignosulfonates, cellulose polymer derivatives
(i.e. HEC, HPMC,
EC), hydrophobically modified alkali swellable emulsions or hydrophobically
modified
ethoxylate urethanes molecular rheology modifiers, Exopolysaccharide (i.e.
Wellan gum,
xantham gum), galactomannans (i.e. guar gum, carob gum), or other
hydrocolloids. In a
preferred embodiment, the rheological admixtures are sodium naphthalene
sulfonate.
[0086] In at least one embodiment of the present disclosure, the core mix may
compose natural
or synthetic fibers which may be uniformly distributed through the core mix or
layered within or
one each side of it to provide reinforcement and core integrity. Such fibers
may be of a single
use or combination use of natural fibers such as cellulose, hemp, cotton,
basalt, or synthetic
fibers such as polyester, polypropylene, polyvinyl a'lcohol, nylon, alkali
resistant glass, carbon,
glass. In such an embodiment, the fibers may have a similar or different
aspect ratio. In a
preferred embodiment, the fibers are composed of polypropylene.
[0087] In at least one embodiment of the present disclosure, the core mix may
include one or
more surfactants added directly to the core mix or through foam generation. In
such an
embodiment, the surfactants may be made of blends of different chemicals
having HLB values
ranging from 5 to 25. In such an embodiment, the principal characteristic of
the surfactants is to
provide a relatively stable air bubble having walls of a certain strength,
thereby ensuring the
bubble stability at a high pH and high calcium content with strong mixing
energy. One example
of an appropriate surfactant is Alpha Olefin Sulfonates.
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[0088] In at least one embodiment of the present disclosure, the proportions
of the foregoing
ingredients is such that the density of the resulting cementitious board is
significantly lower than
conunonly used cementitious board and, ideally, lower than the density of
water. An example of
a set of acceptable and preferred range of ingredients is provided in the
below table:
Acceptable and Preferred Range of Ingredients
Ingredient Acceptable Range (% w/w) Preferred Range (% w/w)
Binders 35 to 75 50 to 70
Normal Weight Aggregates 5 to 50 10 to 20
Lightweight Aggregates 0.5 to 5 0.5 to 3
Chemical Set Admixtures 1.5 to 10 2.5 to 9
Rheological Admixtures 0.5 to 5 0.5 to 1.75
Surfactant 0 to 0.1 0 to 0.01
Water 5 to 20 10 to 20
[0089] In at least one embodiment of the present disclosure, the ratio of
water to binder in the
core mix may range from 0.1 to 0.4, with an ideal ratio of the range falling
between 0.15 and
0.30. It should be appreciated that the ratio of water to binders has a great
effect on core mix
rheology. Additional water added to the core mix reduces viscosity which
increases the
likelihood of segregation between the lightest components, such as, for
example, the lightweight
aggregates, and the heavier components, such as, for example, the binders and
normal weight
aggregate, during manufacture of the cementitious board. To avoid such
segregation, an ideal
range of 0.15 to 0.30 is recommended to preserve a relatively smooth and
uniform board surface
while preventing lightweight aggregates from separating through mesh
reinforcement openings.
[0090] The below table provides experimental data regarding the percent
composition of various
ingredients within a core mix and the resulting ability to embed the core mix
with mesh
reinforcement to create a cementitious board with great compressive strength:
___________________________________ Percent vv/w
Ingredients A
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Binders 42% 48% 63%
Normal Weight Aggregates 39% 31% 13%
Lightweight Aggregates 2% 2% 2%
Chemical Set Admixtures 3% 3% 4%
Rheological Admixture 1% 1% 1%
Surfactant 0% 0% 0%
Water 14% 15% 18%
[0091] As shown above, three experiments were conducted to test the ability to
embed a core
mix with mesh reinforcement to create a cementitious board with great
compressive strength. In
these experiments, the percentage composition of various ingredients was
altered between tests
"A", "B", and "C". During test "A", where the core mix was comprised of 42%
binders and
39% normal weight aggregates, the mesh reinforcement was very difficult to
embed within the
core mix. In an attempt to improve this reinforcement, test "B" was conducted
where the
percentage of binders was increased to 48% in the core mix while decreasing
the normal weight
aggregates to 31%. Although this composition change of the core mix mildly
improved the
ability to embed mesh reinforcement, additional improvement was speculated.
Accordingly, test
"C" was conducted which increased the use of binders further to 63% of core
mix composition
while decreasing the normal weight aggregates composition to 13% and also
increasing the
chemical set admixtures to 4%. This modification to the core mix recipe
dramatically improved
the ability to embed mesh reinforcement to the core mix.
[0092] In at least one embodiment of the present disclosure, the ratio of
lightweight aggregates
to the total is 0.01 to 0.04, with an ideal ratio falling in a range between
0.015 to 0.025. In a
preferred embodiment, the lightweight aggregate is comprised of expanded
closed-cell
polystyrene beads in order to achieve improved rheology which facilitates
embedment of the
cementitious board within the mesh reinforcement.
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[0093] In at least one embodiment of the present disclosure, the lightweight
aggregates are
comprised of expanded closed-cell polystyrene beads which decreased diameter
from those
commonly used in the art. In such an embodiment, expanded closed-cell
polystyrene beads with
an expanded diameter falling in the range of 0.06 inches to 0.130 inches
contribute to improved
rheology while also increasing compressive strength of the core mix in
comparison to expanded
closed-cell polystyrene beads of a larger diameter. An example of a cross-
sectional view of a
cementitious board with small-diameter expanded closed-cell polystyrene beads
is shown in
Fig. 12a. As shown in FIG. 12a, one or more small-diameter expanded closed-
cell polystyrene
beads 500 are within the core mix.
[0094] In a preferred embodiment, the core mix comprises small-diameter
expanded closed-cell
polystyrene beads and larger-diameter expanded closed-cell polystyrene beads
as lightweight
aggregates. In such an embodiment, the inclusion of both small-diameter and
large-diameter
expanded closed-cell polystyrene beads provides a synergy that maximizes the
compressive
strength of resulting cementitious board. In a preferred embodiment, the
quantity of
large-diameter expanded closed-cell polystyrene beads versus small-diameter
expanded
closed-cell polystyrene beads is between 25% and 50%. An example of a cross-
sectional view of
a cementitious board with both small-diameter and large-diameter expanded
closed-cell
polystyrene beads is shown in Fig. 12b. As shown in FIG. 12a, one or more
small-diameter
expanded closed-cell polystyrene beads 500 and one or more large-diameter
expanded
closed-cell polystyrene beads 501 are within the core mix.
[0095] In at least one embodiment of the present disclosure, small-diameter
expanded
closed-cell polystyrene beads have an unexpanded diameter in the range of
0.015 inches to 0.028
inches. In a preferred embodiment, the unexpanded diameter is about 0.019
inches. In at least
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one embodiment of the present disclosure, small-diameter expanded closed-cell
polystyrene
beads have an expanded diameter in the range of 0.030 inches to 0.125 inches.
In a preferred
embodiment, small-diameter expanded closed-cell polystyrene beads have an
expanded diameter
of about 0.075 inches. In at least one embodiment of the present disclosure,
the density of
small-diameter expanded closed-cell polystyrene beads is about 1.1 to 1.4
pounds per cubic foot.
In a preferred embodiment the density of small-diameter expanded closed-cell
polystyrene beads
is about 1.2 to 1.3 pounds per cubic foot
[0096] In at least one embodiment of the present disclosure, large-diameter
expanded closed-cell
polystyrene beads have an expanded diameter in the range of 0.060 inches to
0.130 inches. In a
preferred embodiment, the expanded diameter of large-diameter expanded closed-
cell
polystyrene beads is about 0.120 inches.
[0097] Experiments were conducted to arrive at the foregoing preferred
percentage of
large-diameter expanded closed-cell polystyrene beads versus small-diameter
expanded
closed-cell polystyrene beads to find the greatest compressive strength of
resulting cementitious
board from a core mix containing various percentages. The following table
represents measured
ASTM C109 cube compressive strength (psi) in resulting cementitious boards
from core mixes
over various percentages of large-diameter expanded closed-cell polystyrene
beads versus
small-diameter expanded closed-cell polystyrene beads:
Percent of Large-Diameter ASTM C109 Cube
BPS Versus Small- Diameter Compressive
EP S Strength (psi)
0 856
25% 1018
50% 1014
75% 765
100% 595
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[0098] As shown in the above table, experimental data revealed that a
combination of
small-diameter expanded closed-cell polystyrene beads and large-diameter
expanded closed-cell
polystyrene beads used as a light aggregate within a core mix provides the
greatest resulting
compressive strength for cementitious board. In a preferred embodiment,
therefore, the range of
a percentage of large-diameter expanded closed-cell polystyrene beads versus
small-diameter
expanded closed-cell polystyrene beads used as light aggregate ingredients
within a core mix is
between 25% and 50%.
[0099] It should be appreciated that the use of lightweight aggregates within
a core mix
produces unexpected results outside of the ability to maintain high durability
and low
permeability with a reduced overall weight of resulting cementitious board. In
one instance, the
use of lightweight aggregates, and more specifically small-diameter expanded
closed-cell
polystyrene beads, improves the ability to make a clean cut with a utility
knife or other cutting
apparatus of the cementitious board as compared to normal weight boards or
competitively
situated products.
[001001 It should be appreciated that one reason a lightweight board is easier
to cut is due to the
location of reinforcement mesh such that it may be visible but not delaminate
from the core of a
cementitious board when cut with a utility knife or other cutting apparatus.
It should further be
appreciated that a lightweight board using lightweight aggregates of a small
diameter and
spherical nature with a relatively uniform distribution will allow a clean cut
to a cementitious
board. It should further be appreciated that the relatively small amount of
normal weight
aggregate compared to a normal weight board improves the ability to make a
clean cut It should
further be appreciated that the board being free of aggregates or fillers that
are non-uniform in
shape and/or of a relatively large nature (i.e. such as expanded clay, shale
or perlite, diameter or
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length of 1/8 inch or more) enables a cleaner cut to be made. The lightweight
aggregates possess
a relatively weak bond between them as compared to normal-weight aggregates
such that the
weaker bonds are easy to shear. It should be appreciated, then, that a
cementitious board using
lightweight aggregates and a small amount of normal weight aggregate is more
homogeneous
than if it would contain non-uniform and/or larger aggregates, thereby
enabling a cleaner cut to
be performed.
101001 In another instance of unexpected results, the use of small-diameter
lightweight
aggregates within a core mix improves fire performance of a resulting
cementitious board as
compared to normal weight board. In at least one test, the fire performance of
a cementitious
board with lightweight aggregates produces a fire performance of 5.2 minutes
more than a target
duration of 60 minutes.
101011 In at least one embodiment of the present disclosure, a reinforcing
mesh is adhered to the
face of a panel. It is possible in accordance with the present invention for
example to embed a
mesh in a broad or narrow face of the core such that the mesh is disposed at
or near the surface
of the board so as to enhance the strength of the board or panel, i.e. the
strength of the panel is
enhanced if a mesh is adhered at a core face. The embedment of the reinforcing
fibers just
beneath the surfaces of the core may for example be carried out at a depth of
submersion of mesh
from for example about 0.019" (0.5 mm) to about 0,079" (2.0 mm) or less, e.g,
0.019" (0.5 mm)
or less.
[01021 The core mix may be applied in any desired thickness, for example of
values so as to be
able to obtain a panel having the standard thicknesses of wallboard. A panel
may be produced in
varying thickness depending upon end use: e.g. in thicknesses of 'A", 3/8",
7/16", '/2' , 5/8",
3/4", 1" etc.
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[0103] In accordance with the present invention a cementitious core mix
composition may be
used which when cured has cells present due to entrained or entrapped air.
Accordingly, a core
mix may for example include or comprise a suitable air entrainment or foaming
agent in such
amounts so as to produce the desired or necessary degree of air entrainment.
[0104] As mentioned above the initial side edge meshes and first broad face
mesh may be laid
down on a suitable carrier support web; the carrier support web may for
example advantageously
be of a non-stick material relative to the cementitious material, i.e. the
carrier on which the board
is formed may be of a material to which the cementitious slurry does not
readily adhere, example
material are polyethylene or polypropylene film, 1.0 to 5.0 mils thick,
polyethylene coated Kraft
paper, 30 lbs. to 100 lbs. of strength.
[0105] As mentioned above, however, it may be desired to provide an edge face
mesh which is
not adhered to the edge face so as to avoid having the cementitious
composition covering up a
desired indicia which is to appear on the side edge of a panel. This may be
achieved for example
by providing the above mentioned edge reinforcing web with an at least
substantially water
impervious outer surface opposite the edge face or with a fiber or filament
structure which may
filter out any solids at the surface thereof so as to inhibit a mechanical
bond on setting of the
cementitious material.
101061 The edges reinforcements may, for example extend inwardly from a
longitudinal edge
face approximately 0.5" to 2.5".
[0107] A panel in accordance with the present invention may thus comprise
relatively thin
surface reinforcement elements on the faces thereof so as to provide the panel
with a relatively
high strength. The panel may also have a core which is relatively readily
penetrable by nails,
screws and other fasteners. A panel may be obtained wherein the surface edge
reinforcement
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layers are relatively strong and hard such that a nail or screw may be driven
through the edge of
panel without pre-drilling and without breaking, even when nailed or screwed
almost at the very
limit of the edge of the panel.
[0108] FIGS. 1 to 4 illustrate in a series of cross-sectional views a sequence
of steps in a method
for the manufacture of an example edge reinforced panel in accordance with the
present
invention wherein the longitudinal edge faces are not closed off. In these
figures the reference
numeral 1 indicate a conveyor belt, i.e. a support member and the reference
numeral 2 indicates a
protective film which is supported and advanced by the conveyor belt 1. The
protective film 2 is
wider than the panel to be made.
[0109] Referring now to FIG. 1, a web of a first non-woven oriented glass mesh
3 is shown with
a previously applied Portland cement slurry 4 deposited thereon across its
breadth in a layer.
The first non-woven oriented glass mesh 3 has also previously been laid on the
protective film 2
such that it overlaps a pair of first bands 5 and 6 of polypropylene non-
oriented mesh which were
previously laid on the protective film 2 in parallel spaced apart
relationship, the first bands 5 and
6 being disposed along margin sections 7 and 8. As may be seen the margin
sections 7 and 8 are
covered by the first non-woven oriented glass mesh 3 and by the slurry 4 such
that both the first
non-woven oriented glass mesh 3 and the first bands 5 and 6 are slurried.
[0110] In FIG. 2 a core mix 10 is shown as having been laid upon the slurried
first non-woven
oriented glass mesh 3 so as to be deposited across the breadth thereof in a
layer.
[0111] In FIG. 3 a second non-woven oriented glass mesh 12 is shown as having
been laid upon
the upper surface of the core mix 10 across the breadth thereof. This second
non-woven oriented
glass mesh was laid down under the urging or influence of a vibrating urging
means which urged
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the second non-woven oriented glass mesh 12 into the upper surface of the core
mix, i.e. so as to
embed the second non-woven oriented glass mesh 12 in the top surface of the
core mix 10.
[0112] In FIG. 3 an additional pair of second bands of polypropylene non-
oriented mesh 14 and
15 are also shown in the process of being laid upon the second non-woven
oriented glass mesh
12 in respective margin sections 7 and 8 opposite the previously laid down
first bands 5 and 6.
These second bands 14 and 15 are likewise laid down under the urging or
influence of the
vibrating urging means which urges these bands into the upper surface of the
core mix on top of
the second non-woven oriented glass mesh 12. The bottom of the core mix 10 is
bonded to the
mesh 3 by the slurry 4 or by the core mix itself
[0113] In this manner an edge reinforced panel is formed as shown in FIG. 4.
The edge
reinforced panel has a pair of opposed longitudinal edge faces 19 and 20. Each
of the marginal
sections 7 and 8 has a pair of marginal areas namely areas 22 and 23 and 24
and 25 which are
associated with respective broad faces of the panel.
[0114] FIG. 5 shows a schematic partial cross sectional view of a reinforced
edge of a panel
made in accordance with the steps illustrated in FIGS. 1 to 4. It shows for
example the
longitudinal edge face as not being closed off by for example a mesh bridging
member
connecting respective first and second bands as shall be discussed with
respect to the FIGS. 7 to
12. In this case as may be appreciated the longitudinal edge faces of the core
are exposed. As
may be appreciated from FIG. 5 a longitudinal edge face and a respective pair
of marginal areas
24 and 25 defines a longitudinal marginal edge; similarly for the other
opposed side of the panel.
[0115] FIG. 6 shows a schematic partial cross sectional view of a reinforced
edge of a further
panel made in accordance with the steps illustrated in FIGS. 1 to 4 except
that the first bands
have been omitted from the procedure such that the panel only has edge
reinforcements due to
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the second bands; accordingly the same reference numerals have been used to
designate common
elements. It too shows the longitudinal edge face as not being closed off by
for example a mesh
bridging member such that the longitudinal edge faces of the core are exposed.
[0116] FIGS. 7 to 11 illustrate in a series of cross-sectional views a
sequence of steps in a
method for the manufacture of another example edge reinforced panel in
accordance with the
present invention wherein the longitudinal edge faces are closed off. In these
figures the same
reference numerals are used to designate elements common with those shown in
FIGS. 1 to 6.
[0117] In FIG. 7 a web of a first non-woven oriented glass mesh 3 is shown
with a previously
applied portland cement slurry 4 deposited thereon across its breadth in a
layer. The first non-
woven oriented glass mesh 3 has also previously been laid on the protective
film 2 such that it
overlaps a pair of wide bands 5 a and 6 a of polypropylene non-oriented mesh
which were
previously laid on the protective film 2 in parallel spaced apart
relationship. The wide bands 5 a
and 6 a are disposed along margin sections 7 a and 8 a and are only partially
covered by the first
non-woven oriented glass mesh 3. As may be seen the margin sections 7 a and 8
a are only
partially covered by the first non-woven oriented glass mesh 3 and by the
slurry 4 such that
while the first non-woven oriented glass mesh 3 is totally slurried, the wide
bands 5 a and 6 a are
only partially slurried, i.e. outer portions 30 and 31 of the bands 5 a and 6
a are left unslurried.
On the other hand, if so desired the slurry may be disposed so as not to cover
at all the wide
bands 5 a and 6 a.
[0118] In FIG. 8 a core mix 10 is shown as having been laid upon the slurried
first non-woven
oriented glass mesh 4 so as to be deposited across the breadth thereof in a
layer so as to again
leave uncovered outer portions 30 and 31. Alternatively if so desired the
slurry 4 may extend
outwardly further over the wide bands 5 a and 6 a than the core mix 10 or vice
versa. The slurry
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4 may for example be extended outwardly further than the core mix in order to
facilitate
adherence (e.g. cementing) of the bands to the longitudinal edge face of the
panel core or even
the opposed broad face at a respective longitudinal marginal edge.
[0119] In FIG. 9 a second non-woven oriented glass mesh 12 is shown as having
been laid upon
the upper surface of the core mix 10 across the breadth thereof, again so as
to leave uncovered
outer portions 30 and 31. This second non-woven oriented glass mesh as before
is laid down
under the urging or influence of a vibrating urging means so as to embed the
second non-woven
oriented glass mesh 12 in the top surface of the core mix 10.
[0120] In FIG. 10 the two outer portions 30 and 31 of the wide bands 5 a and 6
a are folded
upwards to an upright position by suitable guide means.
[0121] In FIG. lithe outer portions 30 and 31 are bent or folded by suitable
means over onto
the second glass mesh 12 in respective margin sections 7 a and 8 a so as to
form respective
U-shaped edge reinforcing meshes adhered to the first and second meshes 3 and
12. The bent
over outer portions 30 and 31 are likewise laid down under the urging or
influence of the
vibrating urging means which urges the distal ends of thereof into the upper
surface of the core
mix on top of the second non-woven oriented glass mesh 12.
[01221 In this manner an edge reinforced panel is formed as shown in FIG. 11.
The edge
reinforced panel has a pair of opposed longitudinal edge faces 19 and 20. Each
of the marginal
sections 7 and 8 has a pair of marginal areas namely areas 22 and 23 and 24
and 25 which are
associated with respective broad faces of the panel.
[01231 FIG. 12 shows a schematic partial cross sectional view of a reinforced
edge of a panel
made in accordance with the steps illustrated in FIGS. 7 to 11. It shows for
example the
longitudinal edge face as being closed off by a mesh bridging member 36 of the
U-shaped edge
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reinforcing mesh; this bridging member 36 connects respective first and second
edge strip
members 38 and 39. In this case as may be appreciated the bridging member may
be adhered to
the core mix due to infiltration of cementitious material into or through the
structure of the
bridging member. Also as may be appreciated from FIG. 12 a longitudinal edge
face and a
respective pair of marginal areas 24 and 25 defines a longitudinal marginal
edge; similarly for
the other opposed side of the panel.
10124] As mentioned above an edge reinforced panel in accordance with the
present invention
may comprise a U-shaped edge reinforcing mesh wherein a bridging member need
not be
adhered to a respective longitudinal edge face but may merely abut such face
or as desired be
spaced apart therefrom; in this case the bridging member may for example be
provided with a
water impervious character such that cementitious material from the slurry of
the core mix may
not pass into or through the bridging member during the manufacture of a
panel. It is possible
for example to provide a wide band such as bands 5 and 6 with a preferably
centrally disposed at
least substantially water impervious longitudinally extending zone on the core
side thereof. The
zone may be provide by means of any mechanism which may render the central
zone
impervious, e.g. by applying a water tight tape, by applying a suitable paint,
by applying a wax
material etc., to the central zone. In such case it is possible, for example,
to apply to the opposite
exposed side of the bridging member a desired indicia in the form for example
of a color, words,
etc. Suitable materials are as follows: adhering tape: masking tape,
translucid shipping tape,
electric tape or other self-adhering tape; size: 0.5 to 4 inches wide,
preferably 0.75 inch wide;
made preferably of: polyethylene, paper, but can also be made of other
impervious or
semi-impervious material.
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[0125] Material coatings: acrylic paint, oil paint, varnish, wax, silicone
sealant, applied with
roller or spray equipment on a width from 0.5 to 4 inches wide, preferably
0.75 inch wide. The
coating can be impervious or semi-impervious. Material: non adhering film: 1
to 5 mils thick;
0.5 to 4 inches wide, preferably 0.75 inch wide; made preferably of:
polypropylene,
polyethylene, paper, but can also be made of other impervious or semi-
impervious material.
[0126] FIG. 13 shows a schematic partial cross sectional view similar to FIG.
7 but wherein the
wide band 6 a is provided with a central longitudinally extending, at least
substantially water
pervious zone defined by an at least substantially water proof tape 40 which
is attached
(e.g. glued) to the core side of the band 6 a. A similar water proof tape may
if desired also be
applied to wide tape 5 a. As for the rest of the process as illustrated in
FIGS. 7 to 11 are
concerned they stay the same.
[0127] FIG. 14 shows a schematic partial cross sectional view of a reinforced
edge of a further
panel made in accordance with a process as shown in FIGS. 7 to 11 but with the
modification
shown in FIG. 13. As may be seen the panel differs from the panel illustrated
in FIG. 12 in that
the waterproof tape 40 abuts the longitudinal side edge of the core and is
sandwiched between
the core side edge face and the bridge member 36. The presence of the tape 40
during
manufacture inhibits the bridge member from being adhered to the core, by way
of cementation
or embedding. Since the tape is at least substantially waterproof the outer
exposed surface of the
bridging member, which in this case is provided with lettering in dotted
outline, is not covered
with cementitious material and the lettering is exposed to view in the final
panel product.
[0128] As may be seen from FIG. 14, the tape 40 more or less extends only
across the breadth of
the core side edge face. Alternatively, as desired or as necessary, a
substantially water
impervious tape may extend into one or both of the adjacent marginal areas of
the broad faces.
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As mentioned above, a marginal area may have a grip region and an adhesion
free region.
Referring back to FIG. 14 examples of the position of such adhesive free
regions are designated
by the reference numerals 42 and 43; the grip regions occupy the rest of the
marginal areas. If a
panel is to have one or both adhesion free regions 42 and 43 then the above
mentioned process
for manufacturing described with respect to FIGS. 13 and 14 may for example be
modified by
using a wider water impervious tape. FIGS. 13a and 14 a relate to such a
process for the
provision of a panel having such adhesion free zones along both side edges
thereof; in FIGS. 13a
and 14a the same reference numerals have been used as with respect to FIGS. 13
and 14 to
designate common elements. In FIG. 13a the wider water impervious tape is
designated by the
reference numeral 40 a. As may be seen from FIG. 14a, the tape 40 a in the
final panel
configuration has a U-shape like cross section (if somewhat flattened); i.e. a
U-shape surface
including the surface of the longitudinal or side edge is not adhered to the U-
shaped
reinforcement mesh component, distal end portions only of the strip members
are adhered to the
marginal edge faces in the grip regions. For the configuration shown in FIG.
14a the distal part
of the strip members is adhered to the core in the grip regions 45 and 46.
[0129] In FIGS. 7 to 14 a the first and second edge strip members 38 and 39
are more or less of
equal length. In accordance with the present invention these strip members may
as desired or
necessary be of different length. The FIGS. 15 to 17 show schematic partial
views of example
panels in accordance with the present invention wherein the strip members are
of different
length. FIG. 15 shows a strip member 38 a which is longer than strip member 39
a; FIG. 16
shows a strip member 38 b which is somewhat longer than strip member 39 b;
FIG. 17 shows a
strip member 38 c which is shorter than strip member 39 c.
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10130] For purposes of illustration FIGS. 7 to 13 and 14 relate to panels
wherein the
reinforcement mesh for the broad faces more or less extend the full breadth of
the broad face of a
panel. However, in accordance with the present invention it is advantageous to
have panels
wherein the side edges of the reinforcement mesh for the broad faces do not
extend the full
breadth of the broad face of a panel but are somewhat offset from the panel
edge such as may be
seen in FIGS. 15, 16 and 17. The offset distance may for example be from V8 to
1/4 of an inch.
Other offset distance may also be used keeping in mind however that the edge
reinforcement
mesh are to still overlap the edges of the broad face meshes in the marginal
areas of the broad
faces. The offset regions are designated by the reference numerals 41 a and 41
b in FIGS. 15 to
16. In order to accommodate such offset regions the process steps discussed
above with respect
to FIGS. 7 to 13 and 14 may be modified for example by using broad face meshes
which are still
centered in place as shown in these figures but for which the width at each
side edge is shorter by
the above mentioned amounts (i.e. shortened by from V8 to 1/4 of an inch); in
this case the core
mix would be laid down so as to extend beyond the broad mesh edges for example
by the above
mentioned offset distances.
101311 Turning now to FIGS. 18 to 21, these figures illustrate an apparatus
for the preparation of
an example panel in accordance with the present invention exploiting an
example method of
manufacture also in accordance with the present invention.
[0132] FIG. 18 illustrates an upstream portion of the example apparatus; FIG.
19 illustrates a
central portion of the example apparatus; FIG. 20 illustrates a downstream
portion of the
example apparatus; FIG. 21 illustrates an alternate upstream portion of the
example apparatus
which is similar to that shown in FIG. 18 but which includes a tape
application zone; and FIG. 22
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illustrates an upstream band feeding station for feeding a pair of side
reinforcement band meshes
to the apparatus upstream portion shown in FIG. 18.
[0133] Referring to FIG. 18, the apparatus has a conveyor system comprising an
endless
conveyor belt 50 as well as attendant drive and return rollers; return roller
52 is shown in
FIG. 18; the drive roller (not shown) is located at the other end of the
conveyor belt and is
configured in any suitable manner so as to be able to induce movement of the
belt such that it
travels in a working direction as shown by the arrow. The apparatus also has a
support or
forming table 54. The conveyor system and the table 54 are arranged such that
the conveyor belt
50 is able to slightingly travel over the surface of the table 54 such that
the table is able to
support the conveyor belt as well as any material disposed thereon.
[0134] The apparatus may include a protective film alignment component for
alignment of an
optional protective film 55 onto the conveyor belt. The protective film 55 is
feed from a roll of
such film (not shown). A protective film 55 is laid onto the belt so as to
protect it and avoid the
necessity of applying a release agent thereto. The film 55 should be wider
than the board's
width, for example wider by at least 5" to 7" or more. The protective film 55
may for example
be made of polyethylene 1.0 to 5.0 mils in thickness.
[0135] The protective film alignment component comprises an alignment bar 56
as well as
support members 57 and 58 which maintain the alignment bar 56 a predetermined
distance above
the conveyor belt 50. The alignment bar 56 is suitably fixed to the support
members 57 and 58
(e.g. as by welding, bolting, etc.); the support members 57 and 58 are
similarly fixed to the table
54.
[0136] Further downstream the apparatus has a side edge reinforcement deposit
station for
depositing a pair of spaced apart bands 60 and 62 of reinforcement mesh onto
the protective film.
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The side edge reinforcement deposit station has pair of edge band alignment
components 64 and
66 which are releasably slidable along a transverse rail element 67 fixed to
side edges of the
table by upright support members 68 and 69 such that the rail element 67 is
suitably spaced
above the conveyor belt The rail element comprises two parallel spaced apart
tracks. These
band alignment components are configured so as to be positioned for
depositing, onto the
protective film, the two parallel bands 60 and 62 of reinforcement mesh in the
appropriate
marginal positions according to a panel's or board's desired width. The bands
60 and 62 may be
of sufficient width (e.g. 4" to 5") so as to cover the upper and lower
marginal edge areas (2" to 3"
wide) and provide a 0.5" minimum overlap of the upper and lower broad face
reinforcement
meshes referred to below.
[0137] The bands 60 and 62 of reinforcement mesh may for example be made of a
synthetic
nonwoven non-oriented material. These bands 60 and 62 may for example have a
thickness of
0.010" to 0.020" and a density of 2 to 4 oz. per square yard. The bands 60 and
62 may for
example be of polypropylene. The bands 60 and 62 may for example be in the
form of a roll of a
diameter of 20" to 50" but preferably 30", e.g. in order to give a length of
approximately 500 to
1000 linear yards.
[0138] The band alignment components 64 and 66 each have a rail grip member
respectively
designated by the reference numbers 71 and 72 for gripping the rail element 67
so as to attach
these components to the rail element 67 at a predetermined position thereon.
Each band
alignment component 64 and 66 comprises an upper support arm (respectively
designated by the
reference numbers 74 and 75) and a lower slide bar arm (respectively
designated by the reference
numbers 76 and 77) which are attached to an upright support plate
(respectively designated by
the reference numbers 78 and 79) which projects from each of the rail grip
members 71 and 72
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transversely to the longitudinal axis of the rail element 67. The upper
support arms 74 and 75
project more or less at a right angle from a respective plate 78 or 79 to
which they are fixed in
any suitable fashion (e.g. by welding). The lower slide bar arms 76 and 77 are
respectively
pivotally attached to plate 78 and 79 by any suitable pivot means 80 and 81
(e.g. a hinge). The
band alignment components each respectively have a crescent plate 82 and 83
fixed at the distal
ends of upper support arms 74 and 75; these crescent plates 82 and 83 are each
provided with an
arc shaped alignment slot 84 or 85. The distal end of each of the lower slide
bar arms 76 and 77
respectively has an upturned threaded end portion which extends upwardly at
right angles to the
rest of the slide bar arm through a respective slot 84 and 85. A respective
tightening nut 88 or 89
is disposed on a respective threaded end portion above a respective plate 82
or 83. Just adjacent
the underside of each plate 82 and 83 a respective upper end portion has a
respective transversely
projecting ridge member disposed such that as a respective nut 88 or 89 is
screwed downwardly
the ridge member can abut the underside of a respective plate 82 or 83 so as
to clamp a
respective lower slide bar arm 76 or 77 at a predetermined are position.
Loosening the nuts 88 or
89 allows the lower slide arm bar 76 or 77 to be pivoted about the pivot means
80 or 81 to a
desired arc position.
101391 Each of the rail grip members 71 and 72 is also configured so as to be
able to releasably
clamp a respective band alignment component 64 or 66 at a predetermined
position on the rail
element 67. The grip members 71 and 72 each have upper clamp plates
(respectively designated
by the reference numbers 91 and 92), lower clamp plates (respectively
designated by the
reference numbers 94 and 95) and a pair of releasable tightening bolts
(respectively designated
by the reference numbers 97 and 98). The upper clamp plates 91 and 92 are
provided with
unthreaded openings through which the shafts of the bolts 97 and 98 project.
On the other hand
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the lower clamp plates 94 and 95 are provided with threaded openings which are
able to engage
the corresponding thread of the shafts of the bolts 97 and 98 passing there
into through the slot
between the tracks of the rail element 67. As may be understood rotation of
the bolts 97 or 98 in
one direction will tend to tighten a respective clamp plate to the rail
element 67 for fixing a
respective alignment component 64 or 66 to the rail element 67 while rotation
in the opposite
direction will tend to loosen the grip of the clamp plates on the rail element
67 so that the
alignment component 64 or 66 may be displaced as desired along the rail. The
position of the
slide bar arms 76 and 77 is thus adjustable.
[0140] As is shown in FIG. 18, both slide bar arms 76 and 77 are able to be
maintained at an
angle of 45 degrees with respect to the direction of travel of the conveyor
belt such that the bands
60 and 62 being fed thereto at an angle more or less perpendicular to the
direction of travel of the
conveyor belt 50 are able to change direction and be deposited in parallel
spaced relationship
onto the protective film 55. The adjustability of the band alignment
components 64 and 66
means that they can also be moved to different positions in order to produce
panels of different
width (e.g. panels having a width of 32", 36" or 48" wide boards).
[0141] The bands 60 and 62 may for example be aligned so that their edges are
not outside the
edges of the protective film 55. The distance between the outer edges of the
bands 60 and 62 and
the outer edges of the protective film 55 may for example be from 0" to 0.5".
[0142] Referring now to FIG. 19 the apparatus has a first broad face
reinforcement deposit
station for depositing a bottom or lower mesh layer onto the protective film
55 and the bands 60
and 62. The first broad face reinforcement deposit station has a first mesh
layer alignment
component for depositing the bottom or lower layer of reinforcement mesh 100
onto the
protective film 55 so as to overlap portions of each of the above mentioned
side edge
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reinforcement bands 60 and 62. For the present example apparatus the lower
layer of the
reinforcement mesh 100 is sized and centered so that the distance between the
outer edges of the
reinforcement mesh 100 and respective outer edges of the reinforcement bands
60 and 62 are
more or less the same. The lower layer of reinforcement mesh 100 may be of
fiberglass or
polypropylene.
10143] The first mesh layer alignment component comprises an alignment bar 102
as well as
support members 104 and 105 which maintain the alignment bar 102 a
predetermined desired
distance above the conveyor belt 50. The support members 104 and 105 may be
adjustable or
non-adjustable as desired or necessary.
[0144] In FIG. 19 the support members are shown as being adjustable such that
the alignment
bar may be displaced upwardly and downwardly as well as forwardly in the
direction of travel of
the conveyor belt and backwards in the opposite direction. The following
description will be
given with respect to support member 104 but the same reference numbers will
be used to
designate the common elements of support element 105.
[0145] It should be appreciated that proper mesh embedment depth within
cementitious board is
ideal when the mesh itself is not visible but the pattern it creates on the
top surface of the
cementitious board is slightly visible. If the mesh is embedded too deep in
the cementitious
board, aesthetics and cutting problems will arise when manipulated in its
intended use. If the
mesh is not embedded enough, the mesh will fail to provide the reinforcement
qualities for which
it was added. In at least one embodiment of the present disclosure, the
alignment bar 102 and/or
other components used in mesh depositing will vibrate to assist in achieving a
desired
embedment depth by making the cementitious board surface appear more uniform,
which avoids
streaks and build-up. Any type of vibration may be used, including
electrically driven motor
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equipped vibrators with unbalanced cam shafts, pneumatic turbine vibrators
using eccentric
working unbalanced moment, pneumatic piston vibrators, or any other type of
vibrator that is
able to produce rotary vibration or other type of vibration. In a preferred
embodiment, more than
one vibrating station is used to assist in application and embedment of the
reinforcing mesh. In
such an embodiment, each vibration station is equipped with one or more
vibrating screeds or
bars with a width ranging between and including 4 inches to 12 inches with a
length similar to
the width of the cementitious board being manufactured.
[01461 In at least one embodiment of the present disclosure, vibration is
applied to a slurry or a
core mix to assist in partial embedment of reinforcing mesh. In such an
embodiment, the
vibration of the slurry or the core mix over the reinforcing mesh is at a rate
high enough to assist
in the creation of a strong bond between the reinforcing mesh and the slurry
or core mix but a
rate low enough so as not to embed the reinforcing mesh too deep into the
slurry or create
segregation of the core mix components.
[0147] In at least one embodiment of the present disclosure, vibration is
applied to a slurry or
core mix to assist in partial embedment of reinforcing mesh wherein the slurry
or core mix is
comprised of lightweight aggregate, such as, for example, small-diameter
and/or large-diameter
expanded closed-cell polystyrene beads. It should be appreciated that the use
of any expanded
closed-cell polystyrene bead may hinder the proper depth embedment of
reinforcing mesh into a
forming slurry or core mix. It should further be appreciated that this
hindrance is accentuated
through the increasing use of small-diameter expanded closed-cell polystyrene
beads. It should
be appreciated that the small-diameter expanded closed-cell polystyrene beads,
without such
vibration, may cause a non-uniform thickness of forming cementitious panel
such that
application of a reinforcing mesh occurs at a non-ideal depth. It should
further be appreciated
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that the small-diameter expanded closed-cell polystyrene beads, with too great
of vibration, may
cause the small-diameter expanded closed-cell polystyrene beads to pass
through the reinforcing
mesh and, therefore, create a non-uniform thickness or aesthetic appearance of
forming
cementitious panel such that application of a reinforcing mesh occurs at a non-
ideal depth.
[0148] In at least one embodiment of the present disclosure, the use of
vibration to the slurry or
core mix containing such lightweight aggregates enables the embedment of
reinforcing mesh into
the slurry or core mix to form a cementitious panel with reinforcing mesh at a
proper embedment
and, therefore, high durability and easy cut-ability.
[0149] It should be appreciated that the amount and length of vibration
necessary to assist in
mesh embedment may vary depending on the core mix recipe. If too much
vibration is used for
too long of a duration, segregation of the core components may occur. For
example, lightweight
aggregates, such as, for example, expanded closed-cell polystyrene beads may
float to the top of
the board while heavier components, such as, for example, cement, will be
pushed to the bottom
of the board, thereby creating a possible delamination effect, and/or
technical or aesthetic
problems.
[0150] In at least one embodiment of the present disclosure, there may be one
to several
working stations and/or process stations to assist in the embedment of
reinforcing mesh in a core
mix or slurry. In such an embodiment, each of the stations is equipped with
one or three
vibrating screeds, bars, trowels, rods, plates, or other apparatus that may
create a contact with a
top of a core mix moving downstream on a conveyor. In at least one embodiment
of the present
disclosure, the vibrating apparatuses provide a uniform distributed weight to
the core mix of 35
to 70 lb/sq. ft. In a preferred embodiment, each vibrating apparatus provides
a uniform
distributed weight to the core mix between 45 to 60 lb/sq. ft. In a preferred
embodiment, each
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vibrating apparatus has a width of four inches to twelve inches, with an ideal
width of six inches
to nine inches, and a length similar to the width of the desired width of the
forming cementitious
board.
101511 In at least one embodiment of the present disclosure, a core mix
resides under a vibrating
apparatus between 0.5 seconds and 3.0 seconds. In a preferred embodiment, a
core mix resides
under a vibrating apparatus between 0.75 seconds and 1.8 seconds. It should be
appreciated that
the core mix may reside under one or more vibrating apparatus for any length
of time.
101521 Referring to FIGS. 19, 19a, 19b and 19c the support member 104 has an
upright support
element 107 provided at the top thereof with a crown element 108 fixed thereto
having a
threaded channel. The support member 104 has a first crank 109 provided with a
threaded shaft
110, a crank handle 111 at one end and at the other distal end an abutment
head 112. The
threaded shaft 110 is in screw engagement with the threaded channel of the
crown element 108.
The abutment head 112 is rotatably attached to a further crank body by fixing
the outer shell 115
of a bearing member to the crank body 114 and fixing the inner bearing element
116 which is
rotatable with respect to the outer shell 115, to the abutment head 112. In
this way rotation of
the crank 109 in one direction will cause the head 112 to rotate and push
against the crank body
114 while rotation in the opposite direction will cause the head 112 to pull
the crank body 114.
The support member 104 includes an additional or second crank 117 which is
connected in
analogous fashion to the crank body 114 and an alignment bar attachment member
119 which in
turn is attached to the alignment bar 102 such that rotation of the crank 115
through the crank
body 114 either induces the bar 102 to be raised or to be lowered. With
respect to the second
crank 115, the same reference numbers are used to designate elements which are
common with
the first crank 109.
44
[0153] FIGS. 19a, 19b and 19c show in detail the above described dual crank
system for the
support member 104.
[0154] The apparatus has a slurry station comprising a pair of slurry edger
rail elements 121 and
122, a slurry scrapper or screed bar element 125 and a slurry delivery system.
The purpose of the
slurry *station is to facilitate adherence of the reinforcement mesh 100 to
the core mix by first
embedding the mesh 100 in a slurry layer prior to the deposit of the core mix
thereon; this slurry
layer will also serve to create a smooth side face for the panel. However if
desired this slurry
station may be omitted. If the slurry station is omitted other steps may have
to be taken to ensure
that the reinforcing mesh is adhered to the panel surface in the desired or
necessary fashion e_g_ by
being embedded therein. For example, the formulation of the concrete mix may
be modified so as
to facilitate the embedding of the bottom mesh therein; please see U.S. Pat.
No. 5,221,386 column
8 lines 1 to 31 for a description of such a potential core mix.
[0155] The slurry edger rail elements 121 and 122 are directly attached to the
table 54 by connector
elements 128 and 129 and indirectly by elements 130 and 131 attached to legs
134 and 135 of a
support structure 137 for supporting a slurry holding container 140. The edger
rail elements 121
and 122 are fixed in place such that the lower edge of each of the edger rail
elements 121 and 122
is spaced apart from the table 54 a distance sufficient to allow the conveyor
belt 50, protective film
55 and any desired layer or layers of reinforcing mesh to pass between. This
distance however is
such that the slurry deposited on the lower mesh 100 is inhibited from
spreading laterally beyond
these edger rail elements 121 and 122. The edger rail elements 121 and 122 are
also spaced apart
a desired predetermined distance so as to assure that a predetermined constant
width of slurry is
deposited on the lower mesh 100.
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[0156] The slurry scrapper or screed bar element 125 is attached to the
support structure 137 for
the slurry holding container 140 by support arms 142 and 144 such that the
lower edge of the
screed bar element 125 is spaced apart from the table 54 so as to define a
screed distance (i.e. a
nip) sufficient to allow the conveyor 50, a protective film 55 and any desired
layer or layers of
reinforcing mesh to pass there between. This screed distance however is such
that the slurry
deposited on the lower mesh 100 and which passes under the screed bar element
125 forms a
slurry layer of predetermined depth in which the lower mesh 100 is more or
less embedded. The
screed bar element 125 may be of rubber.
[0157] As may be appreciated, the slurry edger rail elements 121 and 122 and
the slurry
scrapper or screed bar element 125 form a type of U-shaped raised barrier dam
structure having
lower edges which are spaced apart from the table sufficient above described
respective spacing
distances. By suitable manipulation and synchronization of the speed of the
conveyor belt 50
and the flow rate of slurry onto the lower mesh 100 more or less at the mouth
of the dam, slurry
suitably deposited on the lower mesh 100 may be made to backflow and create an
upstream
slurry pool 145 within the U-shaped barrier dam which may be generally deeper
than these
spacing distances. In this manner a slurry layer may be continuously laid down
in which the
lower mesh 100 is embedded. The slurry delivery system comprises the slurry
holding container
140, an agitator 147 and a controllable slurry outlet member indicated
generally by the reference
number 150. The slurry holding container 140 is supported by the support
structure 137, the
container 140 being attached to the support structure 137 in any suitable
fashion e.g. bolting.
The agitator is connected to a motor (not shown) for rotation of the agitator.
The components of
the slurry may be mixed together in a separate container (not shown) and
thereafter be delivered
to the slurry holding container 140 in any suitable fashion (e.g. through
appropriate ducting or
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manually); once in the slurry holding container 140 the agitator functions to
maintain the slurry
in a more or less homogenous mixed state prior to its being released onto the
lower mesh 100.
Alternatively, if desired or as necessary the slurry components may be
delivered in any suitable
fashion directly to the slurry holding tank 140 where they may be mixed due to
the influence of
the rotating agitator 147. The controllable slurry outlet member 150 may
include a valve (not
shown), such as a gate valve, which may be (spring) biased in a closed
position. The valve may
be connected to a solenoid type means whereby in response to an electrical
signal the valve may
be opened so as to release slurry onto the lower mesh 100 at timed intervals
synchronized with
the movement of the lower mesh 100 thereunder. The outlet member 147 is
disposed such that
the slurry deposited on the lower mesh 100 may be maintained within the
confines of the above
described U-shaped barrier dam and form the above mentioned slurry pool 145.
[0158] The apparatus also has a core mix station which is similar in general
makeup to the slurry
station. The core mix station comprises a pair of core mix edger rail elements
155 and 156, a
core mix screeding roller component 158 and a core mix delivery system. The
purpose of the
core mix station is to deposit core mix onto the slurried lower mesh 100 so as
to form a core mix
layer covering the breadth of the lower mesh.
[0159] The core edger rail elements 156 157 are directly attached to the table
54 by connector
elements 159 and 160 and indirectly by elements 161 and 162 attached to legs
164 and 165 of a
support structure 167 for supporting a screed roller 170 such that the lower
edge of each of the
rail elements 156 and 157 is spaced apart from the table 54 a distance
sufficient to allow the
conveyor 50, protective film 55 and any desired layer or layers of reinforcing
mesh to pass there
between. This distance however is such that the core mix deposited on the
slurried lower mesh is
inhibited from spreading laterally beyond these edger rail elements 156 and
157. The edger rail
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elements 156 and 157 are also spaced apart a desired predetermined distance so
as to assure that
a constant width of core mix is deposited on a slurried lower mesh. The core
edger rail elements
156 and 157 may be of high molecular weight polyethylene.
[0160] The core mix screeding roller component comprises a screed roller 170
and the support
structure 167 for holding the roller 170 in place. The roller 170 may have a
(poly)urethane
covered surface. The roller 170 has shall elements 172 and 174 fixed at
opposed ends thereof.
These shaft elements 172 and 174 are each engaged in respective bearing means
(not shown)
provided in the cross members 176 and 178; these bearing members allow the
screed roller 170
to be rotated about a longitudinal axis. The shaft 172 is attached to a motor
(not shown) for
urging the clockwise rotation of the screed roller 170; the motor is suitably
configured for
example to rotate the screed roller 170 clockwise in the same direction as the
conveyor belt 50
but at a speed slower than the speed of the conveyor belt 50.
[0161] The screed roller 170 may be fixed in place or be vertically adjustable
so as to vary the
nip between the roller and the conveyor belt. In FIG. 19 the screed roller is
illustrated as being
vertically adjustable.
[0162] The cross members are vertically displaceable by a crank system
analogous to that
shown in FIGS. 19a, 19b and 19c such that the screed roller 170 may be
displaced up and down
so that the nip between the roller 170 and the conveyor belt 50 may be set to
the desired core mix
layer thickness. The crank system includes a single crank component (the
cranks being
designated by the reference numbers 180 and 181). The side ends of the cross
members 176 and
178 are each provided with key elements slidably engaged in slots on the
inside parts of the
roller support structure 167; one of the slots is designated with the
reference number 184.
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[0163] As may be appreciated, the screed roller 170 and core mix edger rail
elements 155 and
156 also form a type of U-shaped raised barrier core mix dam structure having
lower edges
which are spaced apart from the table 54 sufficient above described respective
spacing distances.
By suitable manipulation and synchronization of the speed of the conveyor belt
50 and the flow
rate of core mix onto the lower mesh more or less at the mouth of this core
mix dam, core mix
suitably deposited on a lower mesh may be made to backflow and create an
upstream core mix
mass 190 within the U-shaped barrier dam which may be generally deeper than
these spacing
distances, (i.e. in particular deeper than the screed roller nip). In this
manner a core mix layer
191 may be continuously laid down over the slurried lower mesh.
[0164] The core mix delivery system comprises the core mix holding container
192, an agitator
193 and a controllable core mix outlet member indicated generally by the
reference number 195.
The core mix holding container 192 is supported by the support structure 196.
The agitator 193
is connected to a motor (not shown) for rotation of the agitator. The
components of the core mix
may be the same as for the slurry but including lightweight aggregate and
normal weight
aggregate and if desired an air entraining agent or other desired or necessary
components.
[0165] In at least one embodiment of the present disclosure, the core mix
contains expanded
closed-cell polystyrene beads as a lightweight aggregate. In a preferred
embodiment, the core
mix contains a mix of small-diameter and large-diameter expanded closed-cell
polystyrene beads
as the lightweight aggregate. It should be appreciated that closed-cell
polystyrene beads require
multiple passes through heated steam in order to achieve expansion suitable
for inclusion in a
core mix. A small-diameter closed-cell polystyrene beads must pass through
heated steam at
least twice to achieve the necessary expansion, with a one to two hour drying
time between
passes. Therefore, a small-diameter closed-cell polystyrene bead may not be
suitable for
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inclusion in core mix without two full passes through heated steam and drying
time of up to four
hours. It should be appreciated that these multiple passes and associated
drying time creates
unnecessary delay in the cementitious board creation process. In some
instances, enabling a
multiple-pass facility for such beads within a plant without incurring
additional delay to the
cementitious board process would require the construction of new or expanded
facilities at great
cost and each additional pass through heated steam would incur expense.
[0166] In at least one embodiment of the present disclosure, small-diameter
closed-cell
polystyrene beads may be expanded in a one-pass process to the appropriate
size. In such an
embodiment, the small-diameter closed-cell polystyrene beads have an
unexpended diameter
range between 0.015 inches to 0.028 inches with a desired expanded range
between 0.03 inches
to 0.125 inches. In such an cmbodiment, each closed-cell polystyrene bead is
preferably
lubricated with a hydrophobic agent (i.e. calcium stearate).
[0167] In such an embodiment, the closed-cell polystyrene beads undergo a
heated steam, with
pressure ranging from 3 to 7 psi and a temperature ranging between 220
Fahrenheit to 240
Fahrenheit. In at least one embodiment of the present disclosure, after the
conclusion of the
heating process, the beads are sprayed with an antistatic agent to prevent
static electricity from
forming. In such an embodiment, the anti-static agent may include anti-static
agents commonly
known to those of skill in art, such as, for example, larostat 5191, Arquad
2ht-75, Atmer, and/or
household fabric softeners and commercial or industrial surfactants, such as
Alpha Olefin
Sulfonates. In such an embodiment, the beads may be sprayed with a hose
attached to a pressure
tank containing the anti-static agent, may be submerged in the anti-static
agent, or other method
such that the anti-static agent is applied to the beads thoroughly.
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[0168] In at least one embodiment of the present disclosure, the components of
the core mix,
including any lightweight aggregates, may be mixed together in a separate
container (not shown)
and thereafter be delivered to the core mix holding container 192 in any
suitable fashion
(e.g. through appropriate ducting or manually); once in the core mix holding
container 192 the
agitator functions to maintain the core mix in a more or less homogenous mixed
state prior to its
being released onto the slurried lower mesh. Alternatively, if desired or as
necessary the core
mix components may be delivered in any suitable fashion directly to the core
mix holding tank
192 where they may be mixed due to the influence of the rotating agitator. The
controllable core
mix outlet member 195 may include a motorised archimedes screw for delivering
core mix onto
the slurried lower mesh at timed intervals synchronized with the movement of
the slurried lower
mesh thereunder; the rotation of the screw may for example be controlled by a
timer mechanism
which controls the energization and denergization of the screw motor. The
outlet member 195 is
disposed such that the core mix deposited on the slurried lower mesh may be
maintained within
the confines of the above described U-shaped barrier core mix dam and form the
above
mentioned core mix mass.
[0169] It should be appreciated that the use of lightweight aggregates and/or
introduction of air
bubbles from use of surfactants decreases the weight of a core mix such that
it may have a
tendency to stick to the screed roller 170. It should be appreciated that the
stickiness may occur
through a suction effect created between the screed roller 170 and the core
mix of a given
rheology. In at least one embodiment of the present disclosure, a forming wire
may be affixed to
the system adjacent to the screed roller 170 to limit the suction effect
created by a lightweight
core mix and assist in maintaining a smooth top surface of resulting
cementitious board.
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[0170] Referring now to FIG. 19d, it is shown an enlarged view of a screed
roller 170 with a
forming wire 171 according to at least one embodiment of the present
disclosure. As shown in
FIG. 19d, in at least one embodiment of the present disclosure, a forming wire
171 may be
affixed to legs 164 and 162 and run parallel to the screed roller 170 at a
close proximity. In a
preferred embodiment, legs 164 and 162 may be adjusted up or down to adjust
the thickness of
extruding board and the forming wire 171 moves with the legs to remain at the
same proximity
to the screed roller 170. It should be appreciated that the forming wire 171
may be affixed to any
component within the system shown in FIG. 19 such that it provides the same or
similar
properties as described herein. The forming wire 171 may also stand
independent from any
component described herein.
[0171] In at least one embodiment of the present disclosure where a forming
wire 171 is
included, the forming wire 171 catches, slices or guides the core mix after
passing under the
screed roller 170 and assists in preventing the core mix from sticking to the
screed roller 170. In
a preferred embodiment, the forming wire 171 is made of music wire, piano
wire, or steel wire
with a diameter ranging from 0.020 inch to 0.030 inch and of a length
sufficient to cover the
entire length of the screed 170. It should be appreciated that it is within
the scope of the present
disclosure for the forming wire 171 to be made of any material such that it
provides the
properties of limiting suction of lightweight core mix as described herein.
For example, it is
within the scope of the present disclosure for the forming wire 171 to be a
roller that rotates with
the screed roller 170 and provides the same suction limiting effect. It is
further within the scope
of the present disclosure for the forming wire 171 to be a metal rod or other
apparatus running
parallel to the screed roller 170 such that the effect of suction of a
lightweight core mix to the
screed roller 170 is reduced. Nevertheless, it should be appreciated that a
wire is advantageous
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because it prevents sticking on the screed roller 170 by acting as a slicer,
similar to a wire cheese
cutter which cleanly cuts cheese as opposed to a doctor blade which may
provide cuts but leave
residue on the blade thereafter. It should be appreciated, then, that the wire
is small enough in a
preferred embodiment to enable cutting of the extruding board while not
accumulating concrete
on its surface and not block extruding board passing underneath the screed
roller 170. It should
be further appreciated that the preferred embodiment has a wire of a diameter
large enough to
avoid rupturing and also prevent excessive wear in an abrasive environment.
[0172] It should be appreciated that the forming wire may be made of steel,
piano wire, music
wire, copper wire, or any other substance. In a preferred embodiment, the
forming wire is
composed of steel with a diameter of about 0.020 inch to 0.030 inch. It should
be appreciated, of
course, that the forming wire may be of any diameter.
[0173] In at least one embodiment of the present disclosure, the forming wire
171 rests at a
position in the range of 0" to 2" downstream of the center of the screed
roller's 170 vertical
position. In a preferred embodiment, the forming wire 171 is adjusted so it
sits just slightly
above the extruded board surface while at the same time slightly touching the
screed roller 170.
In such a preferred embodiment, the forming wire 171 is of a wire tension
great enough to
remain straight when the screed roller 170 is turning and board surface is
extruding. It should be
appreciated that it is within the scope of the present disclosure to position
the forming wire 171
at any range downstream of the screed roller 170 such that it makes connection
with the
extruding board and provides a suction limiting effect as described herein for
a lightweight core
mix.
[0174] Referring now to FIG. 19e, it is shown a rotating rod 175 to prevent
accumulation of
lightweight core mix according to at least one embodiment of the present
disclosure. In at least
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one embodiment of the present disclosure, the rotating rod 175 rotates with
the screed roller 170
and is in slight contact with the screed roller 170 such that it removes any
excessive core mix
from the extruding board without incurring great wear. In a preferred
embodiment, the rotating
rod 175 has a small diameter in a range of 1/16 inches to 1/3 inches and turns
at a rate in the
range of 250 revolutions per minute to 300 revolutions per minute. In such an
embodiment, the
rotating rod 175 provides similar functionality to the forming wire 171 shown
in FIG. 17d but is
advantageous in that it is less resistant to wear and breakage. For example, a
forming wire 171
shown in FIG. 17d may break unexpectedly and require stoppage of formulation
of cementitious
board whereas a rotating rod 175 shown in FIG. 17e is more resistant to wear
and incurs less
breakage. The rotating rod may also be shaped or Profiled instead of being
uniform in diameter.
[0175] In at least one embodiment of the present disclosure, one or more
thinning plates 173
may be affixed under the screed roller 170 near the edges of the extruding
board to shape the
extruded board to be thinner than if the thinning plates 173 were not present.
In a preferred
embodiment, the thinning plates 173 are made of steel and positioned adjacent
to or affixed to
legs 162 and 161. It should be appreciated that the thinning plates 173
provide thinner edges for
the extruding board while maintaining smoothness. It should be appreciated
that it is within the
scope of the present disclosure for any type of apparatus to be affixed in a
manner that provides
thinning as described herein. For example, tape may be affixed to a support
roll (not pictured)
underneath the screed roller 170 on the edges of the extruding board to
provide such thinning
The support roll may also for example be shaped with a specific profile. In
another example,
wood, plastic, or other element may be used. In a preferred embodiment, the
thickness of the
thinning plates 173 or combined thicknesses of other components used to
provide the same effect
(i.e. tape) is between 0.030 inch to 0.060 inch..
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[0176] Turning to FIG. 20 the apparatus has a second broad face reinforcement
deposit station
for depositing a bottom or lower mesh layer onto the core mix layer.
[0177] The second broad face reinforcement deposit station has a layer
alignment component for
depositing a top or upper layer of reinforcement mesh 200 onto the core mix.
For the present
example apparatus the top layer of the reinforcement mesh 200 is sized and
centered so that the
distance between the outer edges of the top reinforcement mesh 200 and outer
edges of the
reinforcement bands 60 and 62 are more or less the same as that for the lower
layer of
reinforcement mesh 100. The top layer of reinforcement mesh 200 may be of
fiberglass or
polypropylene.
101781 The top or upper mesh layer alignment component comprises the same type
of elements
as the above described lower mesh layer alignment component so the same
reference numerals
designated the common components. Essentially the top or upper mesh layer
alignment
component comprises an alignment bar 102 as well as a dual crank system as
described above for
adjusting the position of the bar 102.
[0179] Still referring to FIG. 20 the apparatus has a finishing station. The
finishing station
comprises a pair of guide fork elements 211 and 212, a pair of opposed
finishing edge rail
elements 214 and 216, a floatable screed plate member configured to vibrate
220 and a pair of
edge compression ski components 222 and 224.
[0180] The guide fork elements 211 and 212 each comprise gibbet like support
members and a
prong end having a pair of downwardly extending prongs or fingers generally
designated by the
reference numerals 226 and 227. The gibbet like support members are attached
to the table.
[0181] The finishing edger rail elements 214 and 216 each have guide flange
ends 230 and 232
which taper in the upstream direction such that the inner face tapers towards
the outer face
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thereof and the top face tapers downwardly. The tip ends (one of which is
designated with the
reference number 234) of the guide flange ends 230 and 232 are each disposed
more or less just
below the prong end of a respective guide fork element 211 and 212, i.e. just
below the gap
between the two prongs. The guide fork elements 211 and 212 and the guide
flange ends 230
and 234 cooperate to urge marginal mesh regions as well as the marginal
regions of the
protective film from an initial horizontal position upwardly to a vertically
extending position
from which distal edges thereof may then be bent inwardly and downwardly under
the influence
of the floatable screed plate member 220.
[01821 The finishing edger rail elements 214 and 216 are attached to the table
by connector
elements 236, 237, 238 and 239 such that the lower edge of each of the
finishing edger rail
elements is spaced apart from the table 54 so as to define a nip sufficient to
allow the conveyor
belt to pass there. The rail elements are also spaced apart a desired
predetermined distance so as
to assure that the inner surface thereof may sliding abut respective panel
side edges. If desired
the finishing edger rail elements 214 and 216 may be fixed in place by the
above mentioned
connector elements. However, if desired the edger rail elements may be
laterally adjustable in
order to accommodate panels of different width. For example the connector
elements may have
outer shell and an inner telescoping member and an adjustment bolt; these
elements by way of
illustration are designated with respect to connector 237 respectively by
numbers 250 251 and
252. The bolt may be suitably attached in any manner to the back of the outer
shell so that
rotation of the bolt in one direction will induce the edger rail element 214
to move laterally
inward while a reverse rotation will induce a laterally outward displacement
of the edger rail
element 214.
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[0183] The vibratable floatable screed member 220 comprises an elongated plate
260 and a
vibrator 265 (e.g. a compressed air turbine vibrator) for inducing the plate
260 to vibrate up and
down. The vibrator is connected to a suitable energization source (not shown).
The plate 260
extends between the inner surfaces of the finishing edger rail elements 214
and 216 and is
sufficiently long so as so as to overlap top marginal regions of the top broad
face of the panel
being made. The floatable screed member 220 is made of a relatively light
weight material so
that it is able to essentially float over the upper top mesh and yet be able
to ride over distal parts
of the side edge meshes and protective film as the panel passes thereunder,
i.e. so as to complete
the inward and downward bending of distal edges of the side edge meshes. The
plate 260 may
for example weigh from 20 to 60 pounds, be 3" to 9" wide, and be of aluminum.
The vibratible
floatable screed member 220 is maintained in position against the movement of
the panel there
underneath by bumper or stop elements 270 and 271 which may have rubberized
tips 272 and
273. The vibrator 265 may vibrate the plate 260 so as to induce the upper mesh
as well as the
bent over edge mesh portions overlapping the upper mesh to become embedded in
surface of the
core mix layer.
[0184] As mentioned the protective film and the bands are turned upside-down
(folded) along
the board's edges; the folded over webs are designated by the reference number
221.
Advantageously, sufficient distance (for example 10 to 20 feet) is provided
between the screed
roller and the vibrating bars such that the band may be folded naturally,
releasing the tension that
can cause the band to spring out of the board's surface. The finishing edger
rail elements may
start for example from 20 to 5 feet before the vibrating plat. These edger
rail elements 214 and
216 help the protective film and the bands to be folded without ripples or
uneven tension and
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inhibit the changing of the board dimensions when subject to the
aforementioned under
vibrations.
101851 The apparatus has a pair of edge compression ski components 222 and 224
for smoothing
out the edge regions and providing the edges with an outward taper (J)lease
see FIGS. 15, 16 and
17). The edge compression ski components 222 and 224 each comprise a ski
shaped engagement
element 275 or 276 for riding an edge of the panel. The ski shaped engagement
elements 275
and 276 are fastened to a support bar 280 by respective brackets 281 or 282.
The support bar
280 itself is suspended above and fixed to the table 54 on opposite sides of
the conveyor belt 50
by upright support elements 285 and 286.
[0186] The ski shaped engagement elements 275 and 276 are each attached to
respective
brackets by a pair of nut/shaft systems. The following will describe one such
nut/shaft system in
relation to the component 222; the other nut/shaft systems are the same.
[0187] Referring to component 222 the nut/shaft system comprises a threaded
shaft 290 and a
pair of nuts; an upper nut being designated by the reference number 291. The
threaded shaft 290
is attached at one end to the ski engagement element 275 and the other distal
end engages a
threaded channel in bracket 281; the distal end of shaft 290 extends through
the threaded channel
and engages the upper nut 291. The second nut engages the threaded shaft just
below the bracket
281. The nuts may be made to releasably clamp the shaft 290 to the bracket 281
by suitable
rotation thereof in opposite directions. By displacing the nuts along the
shaft the ski engagement
element may be made to exert more or less pressure on the adjacent panel edge.
One of the
nut/shaft systems of component 222 may be used to vary the pressure of the ski
shaped
engagement element on the outboard side of the edge and the other nut/shaft
system may be used
to vary the pressure on the inboard side of the same edge; in general more
pressure is applied to
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the outboard side of the edge than the inboard side thereof so that an edge
has a somewhat
outwardly tapered shape (please see FIGS. 15 to 17). Additionally the ski
engagement element
275 is disposed such that the ski like tip thereof is upstream relative to the
other end thereof and
the longitudinal axis of the ski element is disposed transversely with respect
the longitudinal axis
of the panel. Although the mechanism for inducing the ski elements to press
down on the edges
has been described in terms of a nut/shaft system, any other type of biasing
means may of course
be used, e.g. a spring biased system, an hydraulic or pneumatic system or a
free weight system.
[0188] Once past the finishing station the elongated panel product may be sent
on the conveyor
to any known type of curing station (e.g. a curing oven). After the curing
station the panel may
then be transferred from the conveyor belt to a cutting station where the
panels are cut to size;
prior to transferring the panel to the cutting station the protective film may
be separated and
recovered. Thereafter the cut panels may be sent to a stacking/packaging
station where the
panels may be moist cured for 3 to 7 days before shipping. The end drive
roller for the conveyor
belt may be located between the curing and cutting stations.
[0189] Referring to FIG. 21 this figure is the same as FIG. 18 but it
additionally shows an
example tape application station for application of an adhesive tape to the
core side of the bands
60 and 62 so as to provide a panel in accordance with the present invention
wherein the bridging
member is not adhered to the core as described above. Since FIG. 21 is except
as noted above
the same as FIG. 18 FIG. 21 will not include all of the reference numbers of
FIG. 18.
[0190] The tape application station includes a pair of rolls of tapes 300 and
301, a threaded tape
support rod 302, a plurality of clamp nuts (each generally designated by the
reference number
304), upright support members 306 and 308, tape alignment components 310 and
311, and tape
pressure application components 313 and 315.
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[0191] The rolls of tape include tape cores through which the tape support rod
302 may be
threaded; a tape core is sized such that a roll of tape is freely rotatable
about the support rod 302.
A roll of tape (300 or 301) is maintained in essentially one predetermined
position by being
bracketed between adjacent clamp nuts 304. The upright support members 306 and
308 have
upper openings through which the threaded rod 302 extends. The rod 302 is
similarly
maintained in place by clamp nuts 304. The alignment components each include a
respective
arm 320 and 321 which bring the tape to an initial close proximity to a
respective underlying
band (60 or 62) such that a subsequent upstream tape pressure application
component 313 or 315
may press down on the tape such that the adhesive thereof causes the tape to
be adhered to the
band. The tape pressure application components 313 and 315 each respectively
includes a
contact element 327 or 328 hinged at one side to a respective support arm 322
or 323; the contact
elements are biased by a respective bias spring 325 or 326 such that the side
of the contact
element opposite the hinged side thereof is biased so as to slide over the
tape urging the tape into
adhesive contact with the band (60 or 62). With the tape in place a panel as
discussed with
respect to FIGS. 13, 13 a, 14 and 14 a may be manufactured.
[0192] Instead of the above described tape mechanism one could use an
analogous paint
applicator, wax applicator etc.
[0193] FIG. 22 shows an example mechanism for feeding reinforcing strips or
bands 60 and 62
to the apparatus forward end illustrated in FIG. 18. As may be seen rolls of
mesh bands 330 and
340 are rotatably attached to shafts 345 and 346; the attachment may in any
suitable fashion so
as to be able to let out the bands as necessary. For example the rolls may
have central cores 350
and 351 which may be able to slide over the shafts 345 and 346 in the manner
of rotatable
sleeves. The rolls may be maintained in place by a block arm releasably
screwed to a respective
shaft 345 or 346; the block arms inhibiting longitudinal axial movement of the
rolls off of the shaft
but not rotation movement about the shaft The mechanism include 45 degree
slide arms 360 and
370 for changing the direction of motion of the bands by 90 degrees as well as
a base support
structure 380 and 381.
[0194] FIG. 23 illustrates in schematic perspective view an edge strength test
for a panel section
400 having an edge reinforcement in accordance with the present invention and
a panel section
410 having a known wrap around reinforced edge such as illustrated in U.S.
Pat. No. 5,221,386
(see FIG. 6 of this patent). Both panels are screwed to spaced wood blocks by
screws; screws 411
are shown as being just adjacent to the outer edge of each panel section_ As
may be seen the prior
art panel 410 has edge failure but not the panel 400 of the present invention
when applying a screw
close to the edge. A panel in accordance with the present invention thus may
permit the installation
of fasteners close to the edge (0.5" or less) without damaging them and thus
provide superior
fastener pull resistance.
[0195] As may be appreciated from the above, in accordance with the present
invention it is in
particular for example, possible to manufacture a cement board having impact
resistant edges by
applying to the edge area of the board a continuous band of synthetic, alkali-
resistant, non-woven
fabric of sufficient strength and elasticity to completely cover the edge area
of the board with a U-
shaped reinforcing mesh without sacrificing the scoring ability of the latter.
In accordance with the
present invention it is possible, for example to obtain a cementitious board
having smooth
longitudinal edges which may be impact resistant by the addition of a U-shaped
non-woven fabric
not embedded nor below the longitudinal minor edge face, i.e. the reinforcing
mesh in the region
of the minor surface may abut or be alternatively cemented thereto.
61
Date Recue/Date Received 2021-04-09
CA 02924051 2016-03-10
WO 2015/039064 PCT/US2014/055745
[0196] As an example of a non-woven non-oriented mesh which may be used herein
may be
described as a polypropylene, staple fiber, needle punched, nonwoven fabric
having the
following characteristics:
i) Mass per unit area: 2,1 oz. per sq. yd.
ii) tensile strength at break: 25 pounds
iii) Elongation at break: 40 to 80 percent
[0197] In addition to the previously provided examples of ingredients
disclosed herein, the
following tables give example compositions for the slurry and core mix as well
as certain
characteristic of a panel made in accordance with the present disclosure:
Board Characteristics for a nominal 1/2" thick board
Physical test Preferred value Generic value
Unit weight 2.3 lbs/sq. ft 2.3 to 3.3 lb/sq. ft
Water absorption 8.60% 5 to 30%
Humidified deflection 0" 0 to 0.01"
Linear variation 0.07 % 0 to 0.10 %
Flexural strength 1100 psi 200 to 2000 psi
Nail pull resistance (wet) 90 lbf 50 to 200 lbf
Nail pull resistance (dry) 90 lbf 50 to 2000 lbf
Tapered edge depth 0.060" 0 to 0.2"
Squaring 0 mm 0 to 0.2"
Freeze/thaw resistance as
of loss 0.32% 0.32%
Fire resistance 1 hr, 2 hrs 45 minutes, 1 hr, 2 hrs, 3 hrs
Flame spread 0 0-10
Smoke density 0 0-10
Wind Load (1/2" x 4 x 8,
studs 16" o.c.) 40 psf 30 to 100 psf
Bond strength of mortar 50 psi 50 to 300 psi
Sound transmission Class 56* Ste 45 to 65 stc
Bending radius 5' 0.5 to 8 feet
Falling ball impact 12" 5 to 16"
62
