Note: Descriptions are shown in the official language in which they were submitted.
CA 02527687 2005-11-24
PRECAST PANEL MOUNTING SYSTEM
FIELD OF THE INVENTION
The present invention relates to precast cladding panels mounted to supporting
structures,
and relates in particular to mounting brackets cast into precast panels.
BACKGROUND OF THE INVENTION
Precast panels of various sizes and shapes are widely used as cladding on
building walls,
serving as components of building envelope systems intended to prevent
infiltration of rain and
outside air into the building. Precast cladding panels are commonly made of
concrete, but may
also be made with other cast materials known in the construction field.
Concrete cladding panels
are common on large structures such as office buildings, but they are also
used on residential
housing structures as an alternative to traditional cladding materials such as
wood siding and
brick.
Whether installed on large or small buildings, it is desirable for cladding
panels to be
mounted in such a way that there will be a continuous air space between the
rear (i.e., inner)
faces of the panels and the supporting structure, while at the same time
providing reliable
structural support for the panels, both to transfer the vertical weight of the
panels to the
supporting structure and to provide anchorage against lateral forces (such as
wind) that may act
on the panels.
The purpose of the air space is to provide a passage through which any water
or moisture
vapour that gets behind the cladding can be directed away from the building
envelope before it
infiltrates other parts of the building. Although caulking or other sealant
materials are typically
used to seal the spaces between cladding panels, the possibility of moisture
infiltration behind
the cladding - as a result of vapour migration, direct penetration of
rainwater (due to sealant
deterioration or other factors), or leakage at roof-to-wall junctures - cannot
be entirely
eliminated. If such moisture is not removed from the building envelope fairly
promptly, it will
tend to migrate further into the building, potentially causing a variety of
problems that could
entail costly maintenance and repairs and could detract from the building's
overall durability and
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value. Such problems may include drywall damage due to moisture absorption,
rot and mold in
wooden construction components (e.g., studs and sheathing), corrosion of non-
rust-resistant
construction hardware, and staining on interior building finishes.
When an air space is provided behind the cladding, moisture can run downward
behind
the cladding to exit points such as weepholes built into the cladding system
at appropriate
locations. The air space also facilitates or enhances air circulation behind
the cladding, helping
to remove moisture vapour before it can condense inside the wall structure,
and helping to dry
out any wall structure components that may have become damp due to moisture
infiltration.
The essential problem facing designers of cladding panel support systems is to
provide
hangers or brackets that can adequately support weight of the panels at a
distance away from the
face of the supporting structure (i.e., so as to provide the desired air
space), without significantly
impeding the passage of water or water vapour through the air space. In this
regard, it is
particularly desirable to avoid or minimize hanger-to-panel connection details
where moisture
might become trapped or its vertical flow impeded.
One approach to this problem is to use vertically-oriented hangers cast into
the rear faces
of the cladding panels, as in Canadian Patent No. 2,169, 585 issued to Kuelker
on February 3,
2004, and similarly in U.S. Patent No. 6,253,515 issued to Kuelker on July 3,
2001. The hangers
used in this system accomplish the desired objectives of providing good
structural support
without significantly impeding air circulation behind the panels. It is
important, of course, for
these hangers to be cast into the panels within fairly close tolerances to
facilitate uniform vertical
alignment of the panels when they are mounted to a supporting structure. As
well, when using
vertically-oriented panel hangers of this or similar type, it will often be
desirable or necessary to
control the horizontal location of the hangers within close tolerances, such
as when it is desired
to attach the hangers directly to primary structural elements (e.g., wall
studs) rather than to
secondary elements (e.g., wall sheathing or strapping). It is readily apparent
that cladding panels
using vertical hangers of this general type cannot be effectively used on
unsheathed walls unless
the hangers coincide with stud locations, or unless horizontal strapping is
installed across the
studs at specific vertical intervals (and at additional cost) to receive the
hanger fasteners.
It is desirable for concrete cladding panels to be stackable as compactly as
possible to
minimize space requirements during storage and shipping. When the panels have
embedded
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hangers that project from the panels' rear faces, there will always be a space
between the stacked
panels equal to at least the thickness of the hangers. Accordingly, the total
height of a stack of
panels may be as much as 20% to 30% greater than the sum of the thicknesses of
the panels,
depending on the relative thickness of the panels and the hanger members. It
is desirable,
therefore, to have a hanger system that reduces or substantially eliminates
the space between
stacked cladding panels, thus significantly reducing storage space
requirements.
The prior art discloses a number of additional examples of hanger systems for
mounting
precast cladding panels to vertical supporting structures, including:
- German Patent Application No. DE 3209746 (Wunsch), filed March 17, 1982;
- French Patent Application No. 82 14147 (Michelet et al.), filed August 16,
1982;
- U.S. Patent No. 4,553,366 (Guerin), issued November 19, 1985; and
- European Patent Application No. 89115208.4 (Isele), filed August 18, 1989.
However, none of these prior art systems addresses all of the problems and
desirable features
discussed above. Moreover, these systems are primarily intended for use in the
construction of
curtain wall systems or mounting large, heavy concrete cladding panels on
large buildings, and
are not conveniently adaptable for use with comparatively small and light
concrete cladding
panels for residential housing structures.
For the foregoing reasons, there is a need for an improved precast panel
support system
that facilitates secure mounting of panels at a uniform distance away from a
vertical supporting
structure without introducing significant impediments to air flow through the
air space thus
created between the rear faces of the panels and the supporting structure.
There is a further need
for a panel support system that facilitates accurate positioning of the
hangers in the panels during
panel casting operations, so as to minimize the likelihood of misalignment of
the mounted
panels. There is an additional need for a panel hanger system in which lateral
location of the
hangers in the panels is not critical in order for the panels to be
conveniently and securely
anchored to vertical support elements, such as sheathed or unsheathed wall
studs. In addition,
there is a need for a panel hanger system that facilitates more compact
stacking and storage of
panels, with the space between stacked panels reduced or eliminated. The
present invention is
directed to these needs.
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BRIEF SUMMARY OF THE INVENTION
In general terms, the present invention is a mounting system for precast
cladding panels
featuring as its main component a mounting bracket that can be cast into a
precast cladding panel
adjacent to the panel's upper or lower edge. One end or portion of the bracket
is intended for
embedment in a precast panel, while the other end or portion is intended to
extend or project at
an angle both rearwardly and laterally away from the rear face of the panel.
The mounting
bracket is configured such that when cast into a precast panel in an
appropriate angular
orientation, the end of the extension portion of the bracket will be disposed
at a distance away
from the rear face of the panel corresponding to the desired air space. At
least one fastener hole
is provided in the extension portion of the bracket, for receiving a fastener
such as a wood screw
to attach the panel to a supporting structure. The bracket also incorporates
abutment means
which, when the bracket is embedded in a panel as described above, will be
substantially in
alignment with the rear face of the panel.
In a typical application, two or more mounting brackets are cast into a panel
adjacent its
upper edge, with two or more brackets being cast into the panel adjacent its
lower edge. The
upper brackets are used to fasten the panel to a supporting structure (such as
a sheathed stud
wall, for instance, in a residential construction scenario), using screws,
spikes, or other suitable
fasteners driven through the fastener openings in the upper brackets. The
upper brackets thus
support the full suspended weight of the panel, while also positioning the
rear face of the panel at
a desired distance away from the face of the supporting structure (i.e.,
corresponding to the
desired air space). After a first panel has been thus fastened to the support
structure, a second
similar panel is positioned above the first panel, with the lower brackets of
the second panel
extending downward behind the first panel. By virtue of their inherent
configuration and the
orientation at which they are cast into the panel, the lower brackets of the
second panel dispose
the rear face of the second panel at the desired distance (i.e., air space
thickness) away from the
face of the supporting structure. At the same time, the abutment means of the
lower brackets of
the second panel extend below the upper edge of the first panel and engage the
rear face of the
first panel, thus effectively locking the second panel behind the first panel,
and preventing the
bottom of the second panel from being displaced outward away from the
structure, without any
direct cormection between the bottom of the second panel and the supporting
structure.
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Accordingly, in one aspect the present invention is a mounting bracket for
partial
embedment in a precast panel having a front face, a generally planar rear
face, an upper edge,
and a lower edge, said bracket comprising:
(a) a rigid, elongate main body having an outer side, an inner side, and two
longitudinal edges, said main body also defining:
a.1 an embedment portion; and
a.2 an extension portion contiguous with the embedment portion, said
extension portion having an inner end; and
(b) abutment means associated with the outer side of the extension portion,
said
abutment means having an outer edge;
wherein when the embedment portion is embedded in a precast panel such that
the extension
portion projects from the rear face of the panel so as to form an obtuse angle
between the inner
side of the extension portion and the rear face of the panel, the outer edge
of the abutment means
will substantially coincide with the plane of the rear face of the panel.
In a second aspect, the invention is a precast panel having a front face, a
generally planar
rear face, an upper edge, and a lower edge, and further having at least two
mounting brackets
embedded in spaced-apart relation adjacent a selected one of said upper and
lower edges of the
panel, each said mounting bracket comprising:
(a) a rigid, elongate main body having an outer side, an inner side, and two
longitudinal edges, said main body also defining:
a.1 an embedment portion; and
a.2 an extension portion contiguous with the embedment portion, said
extension portion having an inner end; and
(b) abutment means associated with the outer side of the extension portion,
said
abutment means having an outer edge;
wherein the embedment portion of each mounting bracket is embedded in the
panel such that:
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(c) the extension portion projects from the rear face of the panel so as to
form an
obtuse angle between the inner side of the extension portion and the rear face
of
the panel;
(d) the outer edge of the abutment means substantially coincides with the
plane of the
rear face of the panel; and
(e) at least a portion of the abutment means is disposed outboard of the
associated
panel edge;
and wherein the outer edges of the abutment means of each bracket is disposed
at a substantially
uniform distance from the inner ends of their corresponding extension
portions, as measured
perpendicular to the plane of the rear face of the panel.
In a third aspect, the invention is a forming system that facilitates accurate
placement of
mounting brackets in precast panels to ensure the creation of a substantially
uniform air space
behind the panels after they are mounted on a supporting structure.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described with reference to the
accompanying
figures, in which numerical references denote like parts, and in which:
FIGURE 1 is an isometric view of a mounting bracket in accordance with a first
embodiment of the invention.
FIGURE 2 is an isometric view of a mounting bracket in accordance with a
second
embodiment.
FIGURE 3 is an elevation of a precast panel with mounting brackets in
accordance with
the invention.
FIGURE 4 is an end view of the precast panel of Figure 3.
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FIGURE 5 is an elevation of an assembly of precast panels as in Figure 3,
mounted to a
vertical supporting structure.
FIGURE 6 is an end view of the assembly of Figure 5.
FIGURE 7A is a sectional detail illustrating a typical field connection of an
upper
mounting bracket in accordance with the embodiment of Figure 1.
FIGURE 7B is a sectional detail as in Figure 7A, additionally illustrating the
optional
use of an auxiliary fastener.
FIGURE 7C is a sectional detail illustrating a typical field connection of an
upper
mounting bracket in accordance with the embodiment of Figure 2.
FIGURE 8A is a sectional detail of a horizontal joint between two mounted
precast
panels having mounting brackets in accordance with the embodiment of Figure 1.
FIGURE 8B is a sectional detail of a horizontal joint between two mounted
precast
panels having mounting brackets in accordance with the embodiment of Figure 2.
FIGURE 9 illustrates a preferred detail for supporting the uppermost panel in
a mounted
assembly of precast panels in accordance with the invention.
FIGURE 10 illustrates a preferred detail for supporting the lowermost panel in
a
mounted assembly of precast panels.
FIGURE 11 is an elevation of a precast panel in accordance with the invention,
mounted
to an unsheathed wall using a corrugated strapping member.
FIGURE 11A is a cross-section of an exemplary embodiment of the strapping
member
shown in Figure 11.
FIGURE 12 illustrates a number of precast panels with mounting brackets in
accordance
with the invention, stacked with protective cushioning material disposed
between panels.
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FIGURE 13 is a perspective view of a multi-cell formwork assembly for casting
multiple
panels, with pockets for receiving mounting bracket inserts in accordance with
the
invention.
FIGURE 14 illustrates the formwork assembly of Figure 13, showing mounting
brackets
with corresponding inserts positioned in one formwork cell, ready to receive
fluid
concrete, and showing one formwork cell already filled with concrete.
FIGURE 15 is a sectional detail of a formwork cell filled with concrete as in
Figure 14.
FIGURE 16 illustrates a mounting bracket in accordance with a third embodiment
of the
invention, in which the bracket is fashion from wire.
FIGURE 17 is a sectional detail of a horizontal joint between two mounted
precast
panels having mounting brackets in accordance with the embodiment of Figure
16.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to Fig. 1, a rigid, elongate mounting bracket 10 in accordance with
a first
embodiment of the invention has an embedment portion 11 and a contiguous
extension portion
13. The point of demarcation between embedment portion 11 and extension
portion 13 is not
precisely defined, but will coincide with the rear face of a precast cladding
panel in which
bracket 10 is embedded, as will be described in detail herein. Bracket 10 is
preferably fashioned
from a corrosion-resistant metal, such as stainless steel, galvanized steel,
or plated steel, but
other materials may also be used provided they have suitable physical
properties. Persons skilled
in the art will appreciate that bracket 10 could be fashioned in accordance
with any of several
known fabrication methods. In the preferred embodiment shown in Fig. 1,
however, bracket 10
is cold-formed from sheet stock. Bracket 10 will preferably be formed with
side edge flanges 14
for increased stiffness, but these are not essential to the invention.
Embedment portion 11 preferably has supplementary anchorage means such as
anchor
tab 12, to enhance the strength and security of the bracket's embedment in a
precast panel. As
shown in Fig. 1, anchor tab 12 may be formed by cutting or punching the
partial outline of
anchor tab 12 and bending it back from the main body of embedment portion 11
to a desired
orientation.
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Extension portion 13 has an outer end 15, which is preferably formed with an
angled lip
16. A primary fastener opening 30 is provided in extension portion 13 adjacent
to outer end 15.
In preferred embodiments, an auxiliary fastener opening 32 is also provided,
and preferably
disposed between primary fastener opening 30 and embedment portion 11.
Extension portion 13
is formed with abutment means, for helping to maintain an air space of
substantially uniform
width between precast panels having mounting brackets 10 and a supporting
structure to which
the panels are mounted (as will be described in greater detail herein). In the
embodiment shown
in Fig. 1, the abutment means is provided in the form of an angled tab 20
which is cut or punched
from the main body of extension portion 13 and formed in a desired
configuration.
The specific physical dimensions of bracket 10 may be varied to suit the
requirements of
a given application, taking into consideration various factors including the
dimensions and
weight of the cladding panel in which bracket 10 is to be cast. To provide
only one example,
brackets 10 approximately 15 mm wide and formed from 24 gauge sheet steel
(approximately
0.024 inches or 0.61 millimeters thick) have been successfully used with
precast concrete panels
measuring up to 460 mm square and having an approximate thickness of 15 mm
thick.
Fig. 2 illustrates a mounting bracket 110 in accordance with a second
embodiment.
Bracket 110 has several features in common with bracket 10, as indicated by
the use of common
reference numerals. What distinguishes bracket 110, however, is that the
abutment means is
provided as a shoulder 120 formed integrally with bracket 110. For greater
clarity in
differentiating bracket 110 from bracket 10, the embedment portion and
extension portion of
bracket 110 are indicated by reference numerals 111 and 113 respectively, with
shoulder 120
forming part of extension portion 113.
Fig. 3 is an elevation of a typical precast cladding panel 50 formed with
mounting
brackets 10 in accordance with the present invention; Fig. 4 is an end view
(or side view) of the
panel of Fig. 3. As illustrated, panel 50 has a front face 52 (which may be
flat or textured as
desired), a generally planar rear face 54, two longitudinal edges 56 (which
may be upper or
lower edges, depending on the orientation of panel 50), and side edges 58. As
shown in the
Figures, panel 50 may be rectilinear in shape, but this is not essential;
panel 50 could take other
geometric shapes without departing from the present invention. For example,
either or both of
longitudinal edges 56 could be partially or completely curvilinear.
Longitudinal edges 56 and
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side edges 58 are preferably beveled as illustrated in the Figures, but this
feature is not essential
for purposes of the present invention; longitudinal edges 56 and side edges 58
could also be
formed at substantially right angles relative to front face 52 and rear face
54 of panel 50.
In a typical arrangement, as shown in Fig. 3, at least two brackets 10 are
cast into panel
50 along each of its longitudinal edges 56. As shown in Fig. 4, each bracket
10 extends at an
angle rearward and laterally away from panel 50, such that each bracket 10 has
a maximum
rearward extension distance 62, as measured perpendicular to rear face 54,
substantially equal to
a desired air space width. By way of example only, an air space of
approximately 0.375 inches
(10 mm) is commonly used for cladding panels in residential and light
commercial construction;
other air space widths may be desirable or necessary depending on specific
building
requirements.
Brackets 10 may be positioned in a variety of patterns along longitudinal
edges 56. In the
preferred configuration shown in Fig. 3, brackets 10 are in vertical
alignment, but they are offset
different dimensions from each of the side edges 58. This is an advantageous
arrangement in
that it makes panels 50 reversible, as can be best seen from Fig. 5, which is
a representative
elevation of three panels 50 arrayed in vertically adjacent fashion. Panels 50
are all the same,
but because of the reversible orientation of their brackets 10 as described
above, adjacent panels
are simply rotated 180 degrees relative to each other so that their respective
brackets 10 do not
interfere.
The specific bracket layouts shown in Figures 3 and 5 are exemplary only, and
persons
skilled in the art of the invention will readily appreciate that brackets 10
can be arranged in a
variety of alternative manners without departing from the present invention.
It is not necessary
for brackets 10 to be positioned along longitudinal edges 56 of panels 50 in
any particular
manner or relationship, provided of course that there is no interference
between the brackets 10
of adjacent panels when they are mounted to a support structure.
Fig. 6 is an end view (or side view) of the panel arrangement in Fig. 5,
mounted on a
vertical support structure 70. As can be seen from Fig. 6, when panels 50 are
placed against
support structure 70, they create an air space 60 having a substantially
uniform width 62, due to
the rigidity of brackets 10 and the angular orientation at which they are cast
into panels 50. Fig.
6 also illustrates how it is only necessary to connect the uppermost brackets
10 of each panel 50
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to support structure 70. This feature is illustrated with greater clarity in
other Figures, as will
now be described in detail.
Fig. 7A is an enlarged detail showing how a typical bracket 10 at an upper
longitudinal
edge 56 is connected to support structure 70. It can also be seen from Fig. 7A
that bracket 10 is
cast into pane150 such that the abutment means (in the form of angled tab 20)
is substantially in
alignment with rear face 54 of panel 50; in other words, angled tab 20 is
disposed at a distance
62 from the point of maximum rearward extension of extension portion 13. To
mount panel 50
to support structure 70, a suitable primary fastener 40 (such as a wood screw,
lag screw, or spike)
is driven through primary fastener opening 30 of each of the brackets 10 along
upper
longitudinal edge 56 of pane150, and into support structure 70.
In the Figures, support structure 70 is conceptually illustrated as comprising
vertical
structural members 71 (such as wood or steel studs) with exterior structural
sheathing 73 (such as
plywood or oriented strand board) in accordance with well-known construction
techniques. This
form of construction is particularly compatible with the present invention
since the structural
sheathing 73 will provide a suitable substrate to receive primary fasteners 40
regardless of the
relative lateral positions of brackets 10 relative to vertical members 71. It
is therefore
unnecessary for brackets 10 to be in alignment with vertical members 71. As
will be seen,
however, it is not essential to have a support structure 70 of this specific
construction in order to
use the panel mounting brackets of the present invention, and in fact they can
be readily used
with support structures 70 that do not have exterior sheathing, or that have
non-structural
sheathing (such as foam insulation panels).
As shown in Fig. 7B, an auxiliary fastener 42 may be driven through auxiliary
fastener
opening 32 to provide a more robust structural connection. When auxiliary
fastener opening 32
is disposed close to embedment portion 11 as shown in Fig. 7A, auxiliary
fastener 42 can have
the additional beneficial effect of creating a moment arm that urges the lower
longitudinal edge
56 of pane150 against support structure 70.
Fig. 7C illustrates a connection much the same as in Fig. 7A, except that in
this case
panel 50 has alternative brackets 110 with integrally-formed abutment shoulder
120. In a
fashion analogous to angled tabs 20 of brackets 10, shoulder 120 is disposed
at a distance 62
from the point of maximum rearward extension of extension portion 13.
Alternative brackets
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110 are connected to support structure 70 in the same manner as brackets 10 in
Figs. 7A and 7B.
Fig. 8A is a section through a typical horizontal field joint between two
cladding panels
50 having brackets 10 in accordance with the invention. For convenient
reference in Fig. 8A
(and in other Figures), the panel above the horizontal joint is referred to as
upper panel 50U, and
the panel below the joint is referred to as lower panel 50L. Similarly, the
suffix "U" or "L" has
been added to the reference numerals of various panel and bracket features to
indicate that they
are referable to upper panel 50U or lower panel 50L (and/or their respective
brackets l0U and
10L) as the case may be.
At a typical horizontal joint as shown in Fig. 8A, lower panel 50L is mounted
to support
structure 70 by connecting brackets 10L (disposed along the upper longitudinal
edge 56L of
lower panel 50L) to support structure 70 as previously described with
reference to Fig. 7A (and,
optionally, Fig. 7B). Lower panel 50L is thus disposed with its rear face 54L
at a distance 62
from the face of support structure 70 (creating desired air space 60). Upper
panel 50U is then
installed by sliding extension portions 13U of brackets l0U (disposed along
the lower
longitudinal edge 56U of upper panel 50U) behind lower panel 50L and into air
space 60, until
lower edge 56U of upper panel 50U abuts upper edge 56L of lower panel 50L as
shown.
Alternatively, upper pane150U may be positioned so as to leave a narrow
vertical space between
upper edge 56L and lower edge 56U, if desired. Because of the substantially
identical
configuration and orientation of brackets l0U and lOL (relative to upper panel
50U and lower
panel 50L respectively), extension portions 13U of upper panel 50U will abut
support structure
70, and angled tabs 20U of brackets 10U will abut rear face 54L of lower panel
50L, while rear
face 54U of upper panel 50U will abut angled tabs 20L of brackets 1OL, thus
bringing rear faces
54U and 54L into substantial alignment. Upper panel 50U may then be physically
connected to
support structure 70 as previously described with reference to Fig. 7A (and,
optionally, Fig. 7B).
Particular advantages of the present invention may be readily appreciated from
the
foregoing discussion of Fig. 8A. There is no physical connection between lower
brackets 10L of
upper panel 50U and support structure 70. Upper panel 50U is effectively
locked in lateral
position behind lower panel 50L, so there is no need for additional means to
provide lateral
stability to the lower portion of upper panel 50U. Upper panel 50U preferably
rests upon lower
panel 50L during installation, thus facilitating both horizontal and vertical
alignment of the
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panels. Rear panel faces 54U and 54L are automatically brought into
substantial alignment
when upper panel 50U is positioned above lower panel 50L as described; this is
beneficial to
facilitate relatively unimpeded drainage of moisture down the rear faces of
the panels.
Because as few as two brackets 10 can be used along each longitudinal edge 56
of a
typical cladding pane150 (or, for small or narrow panels, only a single
bracket 10 on each edge),
and since brackets 10 are fairly narrow in width, brackets 10 present minimal
impedance to the
movement of moisture within air space 60, whether in either liquid or vapour
form.
An additional advantage is obtained in preferred embodiments of bracket 10 in
which
outer end 15 of extension portion 13 is formed with an angled lip 16. As may
be appreciated
from Fig. 8A, angled lip 16U of bracket l0U may be configured to act as a drip
edge, so that
moisture will drip off of angled lip 16U in approximately the middle of air
space 60, with the
desirable effect of minimizing moisture contact with support structure 70.
A further advantage is that the foregoing and other practical benefits are
achieved using
the same mounting bracket 10 on both the upper and lower edges of cladding
panels 50. As a
matter of convenience, all brackets 10 are preferably fabricated with primary
fastener opening 30
(and, optionally, auxiliary fastener opening 32), even though in practice
these openings will
typically not be required for those brackets 10 that will be on lower panel
edges. This simplifies
fabrication and ensures that the required fastener openings will be present
regardless of the
orientation of the panels 50.
Fig. 8B illustrates a typical horizontal field joint similar to that shown in
Fig. 8A, but
with cladding panels 50U and 50L having brackets 110U and 110L in accordance
with the
alternative embodiment shown in Fig. 2. The integrally-formed shoulders 120U
and 120L of
brackets 11OU and 110L function is substantially the same fashion as angled
tabs 20U and 20L
in Fig. 8A.
Fig. 9 is a sectional detail illustrating a preferred method for mounting the
uppermost (or
top) cladding panel in an assembly of cladding panels on a building wall, such
as below a soffit
or eave. In the illustrated detail, top panel 50T has brackets 10T along its
lower longitudinal
edge 56T, but requires no brackets 10 along its upper edge. A spacer channel
74 is attached to
support structure 70 near the top of the wall in conjunction with a cap
flashing 75, using flashing
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fastener 44 as shown. Cap flashing 75 is proportioned to allow for a space 75A
above top panel
50T. Top panel 50T is mounted after the panel below it has been mounted, by
temporarily
positioning top panel 50T at an angle (with its lower edge disposed outwardly
away from the
wall) and sliding its upper edge upward between spacer channel 74 and cap
flashing 75, until
brackets lOT are above the upper edge of lower panel 50L. The lower edge of
top panel 50T is
moved inward and then lowered so that it is supported on the upper edge of
lower panel 50L,
with cap flashing 75 providing lateral support to the upper edge of top panel
50T. Cap flashing
75 will have sufficient strength and flexibility to tolerate outward elastic
deformation during the
installation of top panel 50T, such that it will spring back to the position
shown in Fig. 9 after
top pane150T has been positioned.
The installation of top panel 50T may be facilitated by folding angled lips
16T of
brackets lOT upward as indicated in Fig. 9. This step reduces the distance
that top panel 50T
must be raised above lower panel 50L in order for brackets l OT to be able to
slide behind lower
panel 50L. At the same time, this allows cap flashing 75 to be somewhat
narrower in width.
Persons skilled in the art will readily appreciate that other methods for
mounting top
pane150T are possible. For example, top pane150T could have brackets 10 on
both longitudinal
edges, with the uppermost brackets mounted to support structure 70 in the same
way as for the
lower panels, thereby eliminating the need for spacer channel 74, and with a
cap flashing
installed if necessary or desired after top panel 50T has been mounted. The
suitability of this or
any other method of mounting top panel 50T will depend on the specific
architectural details of
the structure in question.
Fig. 10 is a sectional detail illustrating a preferred method for mounting the
lowermost
(or bottom) cladding panel in an assembly of cladding panels on a building
wall. In the
illustrated detail, bottom panel 50B has brackets lOB along its upper
longitudinal edge 56B, but
requires no brackets 10 along its lower edge. Bottom panel 50B is mounted to
support structure
70 before upper pane150U above it. A spacer channel 74 is first attached to
support structure 70
near the bottom of the wall, using spacer fastener 46 as shown. Preferably, a
continuous or
intermittent bead of mastic 76 or other suitable adhesive material is
deposited on flange 74A of
spacer channel 74. Bottom panel 50B is then mounted to support structure 70
using primary
fastener 40 in the manner previously described.
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Because the center of gravity of bottom panel 50B is disposed at a distance
away from
the face of support structure 70 (and from the point at which brackets lOB are
connected
thereto), the weight of bottom panel 50B induces a counterclockwise moment (as
viewed in Fig.
10) urging the lower portion of bottom panel 50B against flange 74A of spacer
channel 74 and
the mastic 76 deposited thereon. This gravity-induced moment and mastic 76
both help to
maintain the lower portion of bottom panel 50B in lateral position against
support structure 70
without need for direct mechanical fastening. It can be readily appreciated
from Fig. 10 that the
use of auxiliary fastener 42 in conjunction with brackets lOB will induce a
second
counterclockwise moment which enhances the lateral stability of the lower
portion of bottom
panel 50B against support structure 70. For this reason, it is particularly
preferable to use
auxiliary fasteners 42 when mounting bottom panels 50B in a cladding panel
assembly,
especially for exterior installations in which the panel assembly may be
subject to outwardly-
acting negative pressures (due to wind or other factors).
After bottom panels 50B have been mounted, additional panels may be mounted
thereabove in the usual manner, as shown in Fig. 10 (for purposes of which
panels immediately
above bottom panels 50B are referenced as upper panels 50U).
Persons skilled in the art will readily appreciate that other methods for
mounting bottom
panel 50B are possible. For example, bottom panel 50B could have brackets 10
on both
longitudinal edges, thereby eliminating the need for spacer channel 74. In
such alternative
methods, it may be desirable or necessary to provide an additional flashing or
other means for
covering or protecting the brackets on the lower edges of bottom panel 50B.
The suitability of
this or any other method of mounting bottom pane150B will depend on the
specific architectural
details of the structure in question.
Fig. 11 illustrates how strapping members 80 may be used to facilitate the
mounting of
cladding panels having brackets 10 on a support structure 70 that incorporates
spaced vertical
studs 71 but has no exterior structural sheathing. Strapping members 80 are
positioned
horizontally across studs 71 and fastened thereto using strapping fasteners
82. As may be seen
from Fig. 11, strapping members 80 have a sufficient width W so that when
positioned
straddling intended horizontal panel joint locations, they will provide a
surface against which the
extension portions 13 of brackets 10 can abut, and into which primary and
auxiliary fasteners 40
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and 42 may be driven as required (in lieu of structural sheathing).
In the preferred embodiment shown in Fig. 11 (and in cross-section in Fig.
11A),
strapping members 80 are cold-formed channels made from rust-resistant sheet
steel, with
closely-spaced perforations to facilitate installation of fasteners 82, 40,
and 42 without need for
field drilling. However, regular dimension lumber (e.g., one-by-threes) or
alternative cold-
formed metal shapes could be used instead of the illustrated strapping members
80.
Where stud walls are sheathed with exterior foam insulation panels, strapping
members
80 may be applied against the exterior faces of the foam panels, with
strapping fasteners 82
passing through the foam panels before engaging studs 71. Where strapping
members 80 are
channels as in Figs. 11 and 11 A, the channel flanges 80A will be pressed into
the foam.
Fig. 12 illustrates how the use of mounting brackets 10 in accordance with the
present
invention facilitates compact stacking of cladding panels 50 on a pallet 84
(or other supporting
surface) for purposes of storage and shipping. Because of their angular
orientation, as well as
their positioning very close to the longitudinal edges of panels 50, brackets
10 present little or no
interference with adjacent stacked panels. Therefore, panels 50 can be stacked
with little or no
space between them. It will generally be desirable, however, to provide
cushioning means 86
between panels in a stack, to prevent panel damage during shipping and
handling (especially to
the outer panel faces, which typically will be exposed to view after
installation). The cushioning
means 86 could be in the form of resilient matting, heavy cardboard, wood lath
strips, or other
material that will not mar cladding panel surfaces.
Figs. 13, 14, and 15 illustrate a preferred forming system for casting
cladding panels
having brackets 10 in accordance with the present invention. Although
individual panel forms
could be used, it is preferable and more efficient to use a multi-panel
forming frame 90 as shown
in Figs. 13 and 14. Forming frame 90 has multiple casting cells 92, typically
with two (or more)
bracket pockets 94 formed into frame 90 in desired positions along opposing
edges 93
(corresponding to the longitudinal edges of the panels 50 to be cast in cells
92). As best seen in
Fig. 15, each bracket pocket 94 has a bearing surface 94A for receiving angled
tab 20 of a typical
bracket 10. Bearing surface 94A also serves as a casting line guide; i.e.,
when a casting cell 92 is
filled to the level of bearing surfaces 94A of its corresponding bracket
pockets 94, rear face 54 of
the resultant precast panel 50 will substantially coincide with angled tab 20,
thus helping to
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ensure that extension portions 13 of brackets 10 will extend perpendicular to
rear face 54 a
distance 62 corresponding to the desired air space width, as previously
described.
To facilitate the casting of bracket 10 into panel 50 at a desired angular
orientation,
bracket 10 preferably will have an anchor tab 12 as previously described,
dimensioned and
configured such that it will rest against the inner surface of casting cell 92
so as to help maintain
bracket 10 in the desired orientation during the panel casting operation, with
the fluid pressure of
the concrete (or other casting material) tending to hold anchor tab 12 in
position against the
casting cell surface.
As illustrated in Figs. 14 and 15, the maintenance of the bracket position
during panel
casting may be further facilitated by encasing part of the extension portion
13 of each bracket 10
in a resilient plug 96 that helps to hold bracket 10 in the desired angular
orientation. This
preferred feature may be achieved using a bracket plug mold (not shown) having
appropriately
shaped casting cells into each of which a bracket 10 may be positioned,
whereupon the casting
cells may be filled with a suitable liquid compound (e.g., latex or silicone)
that will cool or cure
to form resilient plug 96 partially encasing extension portion 13 as shown in
Fig. 15. Brackets
10 with resilient plugs 96 may then be positioned in bracket pockets 94 as
illustrated by way of
example with reference to casting cell 92A in Fig. 14. The next step is to
fill casting cells 92
with concrete (or other casting material) to form cladding panels 50 as
illustrated in plan view
with reference to casting cell 92B in Fig. 14 and in section in Fig. 15. After
panels 50 have
cured, resilient plugs 96 may be easily pulled off of brackets 10 and
discarded.
Figs. 16 and 17 illustrate a third embodiment of the mounting bracket of the
present
invention. As shown in Fig. 16, alternative bracket 210 is formed from metal
wire of a gauge
suitable to provide the structural strength and stiffness required for
specific panel applications.
Bracket 210 has embedment portion 211 and extension portion 213 analogous to
embedment
portion 11 and extension portion 13 of the previously-described bracket 10.
Bracket 210 is twist-
formed to create a fastener opening 30 analogous to that of bracket 10, and to
form abutment
means in the form of a shoulder 220 analogous to shoulder 120 of alternative
bracket 110.
It will be readily appreciated by those skilled in the art that various
modifications of the
present invention may be devised without departing from the essential concept
of the invention,
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and all such modifications are intended to be included in the scope of the
claims appended
hereto.
In this patent document, the word "comprising" is used in its non-limiting
sense to mean
that items following that word are included, but items not specifically
mentioned are not
excluded. A reference to an element by the indefinite article "a" does not
exclude the possibility
that more than one of the element is present, unless the context clearly
requires that there be one
and only one such element.
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