U.S. patent application number 12/433202 was filed with the patent office on 2009-11-05 for wall panel system.
Invention is credited to Robert T. Griffiths.
Application Number | 20090272055 12/433202 |
Document ID | / |
Family ID | 41256186 |
Filed Date | 2009-11-05 |
United States Patent
Application |
20090272055 |
Kind Code |
A1 |
Griffiths; Robert T. |
November 5, 2009 |
WALL PANEL SYSTEM
Abstract
A wall panel system includes a mounting bracket with a
longitudinally extending first channel and a longitudinally
extending second channel, and a wall panel with a perpendicular
flange around its periphery. The wall panel is attached to the
mounting bracket by a clip attached to the wall panel adjacent the
flange, the clip having an engaging element with a first portion
and a second portion. The clip is secured to the mounting bracket
by either the first portion of the engaging element mating with the
second channel, or the second portion mating with the first
channel. The first portion of the engaging element and the second
channel each include a protrusion, the interaction of the
protrusions causing the first portion to snap into the second
channel.
Inventors: |
Griffiths; Robert T.; (Elk
River, MN) |
Correspondence
Address: |
Jon D. Wood, Chief I.P. Counsel;Bridgestone Americas Holdings, Inc.
1200 Firestone Parkway
Akron
OH
44317
US
|
Family ID: |
41256186 |
Appl. No.: |
12/433202 |
Filed: |
April 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61049190 |
Apr 30, 2008 |
|
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|
Current U.S.
Class: |
52/309.3 ;
52/587.1 |
Current CPC
Class: |
E04F 13/081 20130101;
E04F 13/0889 20130101 |
Class at
Publication: |
52/309.3 ;
52/587.1 |
International
Class: |
E04C 2/20 20060101
E04C002/20; E04C 2/38 20060101 E04C002/38 |
Claims
1. A wall panel system comprising: a mounting bracket having a
longitudinally extending channel; a wall panel having a planar
surface and flanges extending from two opposing edges of said
planar surface; a clip attached to said wall panel adjacent said
flange by an adhesive system, said clip having an engaging element;
wherein said clip is secured to said mounting bracket by said
engaging element mating with said channel.
2. The wall panel system of claim 1, wherein said clip is attached
to said wall panel without the use of mechanical fasteners.
3. The wall panel system of claim 1, wherein said mounting bracket
includes at least one planar surface, and where a fastener passes
through said planar surface into a building surface.
4. The wall panel system of claim 1, wherein said clip includes a
right-angled portion that is mated with a corner on said wall panel
created by a body portion of said wall panels and one of said
flanges and said adhesive system is positioned between said
right-angled portion and said corner.
5. The wall panel system of claim 1, wherein said clip includes a
projection extending from said wall panel and supporting said
engaging element.
6. The wall panel system of claim 5, wherein said engaging element
includes a first shoe portion and a said second shoe portion each
extending from an end of said projection in opposite directions,
and each being substantially parallel with said planar surface of
said wall panel.
7. The wall panel system of claim 1, wherein said adhesive system
includes an acrylic adhesive.
8. The wall panel system of claim 7, wherein said adhesive system
further includes an accelerator.
9. The wall panel system of claim 1, wherein said clip is secured
to said mounting bracket by a fastener.
10. The wall panel system of claim 1, wherein said clip further
includes a slot, and where a spline is received in said slot.
11. An attachment system for a wall panel system having wall
panels, the attachment system comprising: a plurality of clips
having an engaging element, said clips being operatively attached
to opposing edges of the wall panels by an adhesive system; and a
plurality of mounting brackets having a first channel and a second
channel; wherein said clips are secured to said mounting bracket by
said engaging element mating with one of said first channel and
said second channel and wherein said adhesive system includes an
acrylic adhesive.
12. The attachment system of claim 11, wherein said clip is
attached to said wall panel without the use of mechanical
fasteners.
13. The attachment system of claim 11, wherein said engaging
element includes a first shoe portion and a second shoe portion,
said first portion of said engaging element and said second channel
each include a protrusion, the interaction of said protrusions
causing said first portion to snap into said second channel.
14. The attachment system of claim 11, wherein said clip includes a
right-angled portion that is mated with a corner on a wall panel
and said adhesive system is positioned between said right-angled
portion and said corner.
15. The attachment system of claim 14 wherein said clip includes a
projection extending from said wall panel and supporting said
engaging element and where said first shoe portion and said second
shoe portion of said engaging element extend from a distal end of
said projection in opposite directions, each being substantially
parallel with a body portion of said wall panel.
16. The attachment system of claim 11, wherein said adhesive system
further includes an accelerator.
17. A wall panel system comprising a clip attached to a wall panel
by an adhesive system that bonds the clip to the wall panel, the
cured adhesive bond being characterized by a tensile strength at
break of at least 25 MPa.
18. The wall panel system of claim 17, wherein said clip is
attached to said wall panel without the use of mechanical
fasteners.
19. The wall panel system of claim 17, the cured adhesive bond
being further characterized by an elongation of at least 25%.
20. The wall panel system of claim 17, the cured adhesive bond
being further characterized by a Young's Modulus of at least 800
MPa.
21. The wall panel system of claim 17, the cured adhesive bond
being further characterized by a glass transition temperature of at
least 68.degree. C.
22. The wall panel system of claim 17, the cured adhesive bond
being further characterized by a lap shear at room temperature of
at least 15 MPa.
23. The wall panel system of claim 17, the cured adhesive bond
being further characterized by a lap shear at 82.degree. C. of at
least 10 MPa.
24. The wall panel system of claim 17, the cured adhesive bond
being further characterized by a lap shear after five hundred hours
of salt spray exposure of at least 15 MPa.
25. The wall panel system of claim 17, the cured adhesive bond
being further characterized by a lap shear after 14 days at
38.degree. C. and 100% relative humidity of at least 16 MPa.
26. The wall panel system of claim 17, the cured adhesive bond
being further characterized by a lap shear at -34.degree. C. of at
least 14 MPa.
27. The wall panel system of claim 17, the cured adhesive bond
being further characterized by a T-peel of at least 3.0 N/mm.
Description
[0001] This application gains the benefit of U.S. Provisional
Application No. 61/049,190 filed Apr. 30, 2008, which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] One or more embodiments of this invention relate to an
architectural wall panel system designed to cover an interior or
exterior building surface. More specifically, one or more
embodiments relate to an architectural wall panel system employing
high strength bonding adhesives to attach mounting clips to the
wall panel.
BACKGROUND OF THE INVENTION
[0003] Architectural wall panel systems, including both metal and
composite wall panel systems, have been used extensively for some
time, primarily in the commercial and industrial building markets.
In recent years the popularity of composite wall panel systems, in
particular, has been increasing steadily. There are a number of
factors that may be credited for the wide-spread and increased use
of such wall panel systems. One such factor is the high cost to
construct commercial and industrial buildings, which tend to be
relatively large, from stone or brick. Wood is not a suitable
substitute due to the large loads the buildings supporting
structure must withstand. Another factor affecting the increased
use of metal and composite wall panel systems is the high
durability of the systems. Both the metals and composites used to
make the panels for wall panel systems are highly resistant to
damage from sun, dirt, moisture, fire, and many other environmental
elements. Consequently, the metal and composite wall panel systems
have a long life, and may require less maintenance than other
alternative building materials and systems.
[0004] Architectural wall panel systems can generally be placed
into one of two categories: Face-sealed architectural panel systems
or vented rain-screen architectural panel systems. Face-sealed
architectural panel systems include those systems that have a
sealant in both the horizontal and vertical joints between adjacent
wall panels. The sealants make the wall panel system impermeable to
air and water, and may include caulking, gaskets, or other sealants
with a similar function. Vented rain-screen architectural panel
systems are those systems designed to allow permeability through
the joints between adjacent wall panels. The permeable joints allow
for breathability and rapid pressure equalization within the wall
panel system to prevent pressure buildups behind the wall
panels.
[0005] Architectural wall panel systems have many advantages, as
discussed above, however, these systems may also present a number
of challenges and disadvantages. One such challenge is the thermal
expansion and contraction of the wall panels. The metal and
composite materials used most commonly in architectural wall panel
systems are subject to natural expansion and contraction due to
changes in atmospheric conditions, including heat and humidity. If
a means of accommodating this inherent thermal cycling is not
provided in the attachment system of the architectural wall panel
system then the panels can become warped and cracked, requiring
repairing or replacement.
[0006] Another challenge that may be associated with architectural
wall panel systems is directly related to the first issue of
thermal cycling, and relates to the effectiveness of sealants used
in joints between adjacent wall panels in face-sealed architectural
panel systems. Because the joints increase and decrease in size
during thermal cycling, sealants often become dislodged and/or
cracked and are thereafter ineffective at preventing the
infiltration of air and water. As a result, sealants used in
face-sealed architectural panel systems have proven disappointingly
ineffective.
[0007] An additional disadvantage associated with many
architectural wall panel systems is the complexity of the system,
including the number of pieces and parts needed and the extensive
time and labor required to install the complex system. In
particular, where a form of an attachment clip is used to secure
the wall panels to the substructure, each clip must typically be
fastened to the wall panel and to the substructure, either directly
or indirectly. This means that if an extremely high number of
fasteners are used, it results in a great deal of time and effort
spent in installation of the systems just to secure the clips to
the panels prior to attaching the panels to the structure.
[0008] A further disadvantage is that the weight of the wall panels
can cause a shearing moment on the clips of the system. Until now,
mechanical fasteners have been required to counteract this shearing
moment. Common adhesives, such as, for example, silicone adhesives,
have not had the necessary shear strength to secure the clips to
the wall panels, necessitating the continued use of fasteners.
Furthermore, silicone adhesives take a long time to cure, and are
not conducive to additional finishing steps such as sanding and
painting.
[0009] A number of different attachment systems have been
introduced and employed in an attempt to overcome the challenges
and alleviate the disadvantages discussed above. One known
attachment system includes a plurality of locking members secured
directly to, or formed integrally with, the outer surface of the
return flanges of wall panels. The locking members secure the panel
to a retaining member, which is itself secured to a surface of a
building structure. The locking members are shaped such that they
may be forced into a channel, but cannot be removed from that
channel, such as angled surfaces with an apex adjacent the
retaining member that resemble half of an arrowhead. The system may
also optionally provide a drainage channel to carry water and other
debris away from the surface of the building structure. While this
attachment system allows for more efficient installation of an
architectural wall panel system, it suffers from the disadvantage
mentioned above relating to thermal cycling of the wall panel
system because it does not allow for movement of the wall panels.
In addition, the attachment system suffers from a number of new
disadvantages, such as not providing adequate attachment strength
to withstand some natural weather conditions, and making it
extremely difficult to repair or replace installed wall panels as
the locking members prevent the panel from being removed from the
retaining members.
[0010] Other known attachment systems for securing wall panels of
an architectural wall panel system to a building surface utilize
some form of an insert wedged between the two adjacent flanges of
adjacent wall panels, while the flanges are received in a channel.
The insert is secured between the two flanges by a fastener, and
fits snuggly therebetween to provide a seal against water and air
infiltration. The insert may be made of an elastomeric material to
allow for thermal expansion and contraction of the wall panels.
This system, however, uses a high number of parts, and the thermal
cycling of the system is limited by the small amount of movement
allowed by the elastomeric insert. Furthermore, the elastomeric
insert is subject to wear from the natural elements it will be
exposed to, and subject to failure due to these elements and
repeated expansion and contraction as a result of the thermal
cycling of the wall panel system.
[0011] Additional attempts at improved attachment systems have
included attachment systems utilizing variously shaped flanges
extending along at least one edge of the wall panel to facilitate
attachment of the panel to a building surface; attachment systems
using rotatable retaining members secured to the mounting surface
that rotate between a first (narrow) position designed to allow
placement of the wall panels and a second (broad) position
extending into slots in the wall panel flange to secure the panel
in place, such as, for example, a T-shaped retaining member that
rotates about an axis parallel to the wall panel flanges; and
attachment systems having vents and filler strips which slide into
grooves and are positioned within the gaps between adjacent wall
panels to provide a watertight seal while allowing air flow
therethrough. None of these attachment systems has proven
noticeably advantageous over conventional attachment methods in
providing a more efficient, reliable, and practical means of
attaching architectural wall panels to the surface of a
structure.
[0012] There is therefore a need for an improved architectural wall
panel system, and specifically an improved attachment system for
attaching architectural wall panels, that alleviates one or more of
the disadvantages discussed herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a perspective view of a wall panel system
according to the concepts of at least one embodiment of the present
invention.
[0014] FIG. 2 is a fragmentary sectional view of a portion of the
wall panel system of FIG. 1 including a mounting bracket and clips
secured to wall panels.
[0015] FIG. 3 is a sectional view of a clip secured to a
fragmentary portion of a wall panel flange according to the
concepts of at least one embodiment of the present invention.
[0016] FIG. 4 is a sectional view of a mounting bracket secured to
a fragmentary portion of a wall surface according to at least one
embodiment of the present invention.
[0017] FIG. 5 is a rear perspective view of an exemplary wall panel
and clip arrangement according to the concepts of at least one
embodiment of the invention.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0018] In one or more embodiments of the present invention an
architectural wall panel system (hereinafter referred to as wall
panel system) is provided, and is generally indicated by the
numeral 20 in FIG. 1. With reference to FIG. 2, an exemplary wall
panel system 20 is shown as installed on a building surface 24.
Wall panel system 20 includes a plurality of wall panels 22
positioned adjacent to one another on a surface, such as building
surface 24. While reference will be made herein to building surface
24, it should be appreciated that wall panel system 20 may be used
on any desired surface, whether interior or exterior, and reference
to building surface 24 should not be interpreted as limiting the
scope of the invention.
[0019] Wall panels 22 may be made of any suitable material. These
include those materials that have the strength and wear
characteristics to withstand the natural forces and elements that
act upon the wall panel system. These materials will be readily
apparent to a person of ordinary skill in the art. In one or more
embodiments wall panels 22 may be made of metal, and in certain
embodiments wall panels 22 are made of aluminum. In other
embodiments, wall panels 22 may be made of a composite material. In
still other embodiments, wall panels 22 may be made of ACM, or
architectural composite material, as is well known in the industry.
Wall panels 22, as shown in the figures, have a rectangular shape,
however other shapes may be employed without deviating from the
scope of the invention.
[0020] Wall panels 22 are positioned adjacent to one another with a
gap, generally indicated by the numeral 25, therebetween to
facilitate installation and thermal cycling, as will be discussed
in greater detail below. Each wall panel 22 has a top edge 26, a
bottom edge 28, and left side edge 30, and a right side edge 32.
Gaps 25 are formed between the adjacent edges of two panels, such
as, for instance, a horizontal gap 25 between top edge 26 of a
lower panel and bottom edge 28 of an upper panel positioned
immediately above the lower panel. Similarly, vertical gaps 25 are
formed between a left side edge 30 and a right side edge 32 of
adjacent panels.
[0021] As is apparent from FIG. 1, wall panel system 20 may be
adapted to be used to cover inside and outside corners, soffits,
copings, window peripheries, and other architectural features that
may be present on building surface 24. In one or more embodiments
the adaptation of wall panel system 20 to the architectural
features of building surface 24 may be accomplished by varying the
dimensions of wall panels 22. Thus, in at least one embodiment of
the invention, wall panels 22 may be of different shapes and sizes
as needed to properly cover building surface 24.
[0022] In one or more embodiments wall panel 22 is generally pan
shaped having a body portion 27 and side portions, also referred to
as side flanges or flanges, extending from the edges of body
portion 27. Body portion 27 may have any desired size, depending
upon the desired appearance of wall panel system 20 and the
engineering design constraints relating to wind forces and other
factors that may limit the dimensions of wall panel 22 in one or
more ways. In one or more embodiments, such as the embodiment shown
in the figures, a rectangular shaped wall panel 22 is provided with
body portion 27 having a height, or distance between top edge 26
and bottom edge 28, of between approximately 3 inches and 72
inches, in other embodiments between approximately 6 inches and 60
inches, and in still other embodiments between 6 inches and 48
inches. Similarly, body portion 27 may have a width, or distance
between left side edge 30 and right side edge 32, of between
approximately 3 inches and 180 inches, in other embodiments between
approximately 6 inches and 144 inches, and in still other
embodiments between 6 inches and 120 inches.
[0023] The height and width of body portion 27 may differ, creating
a rectangular shaped body portion 27, or they may be equal, thereby
making body portion 27 square in shape. In one or more embodiments
wall panel 22 may have a depth of between approximately 0.5 inches
and 6 inches, in other embodiments a depth of between 0.5 and 3
inches, and in a preferred embodiment a depth of approximately
0.875 inches. Wall panel 22 may also include one or several of a
variety of finishes or textures to provide a desired appearance, as
is well known in the art.
[0024] The side flanges of wall panel 22 extend a relatively short
distance from body portion 27, as compared with the overall
dimensions of wall panel 22. The flanges extend from each edge so
that top edge 26, bottom edge 28, left side edge 30, and right side
edge 32 each has a flange extending therefrom, referred to
hereinafter as top flange 36, bottom flange 38, left side flange
40, and right side flange 42 (FIG. 5). In one or more embodiments
flanges 36, 38, 40, 42 may be connected at the corners of body
portion 27, and in other embodiments a gap may exist between
adjacent flanges at the corners of body portion 27.
[0025] An attachment system 50 useful to secure wall panels 22 to
building surface 24 is shown in FIG. 2. As can be seen in FIGS.
2-4, attachment system 50 includes clips, generally indicated by
the numeral 52, attached to wall panel 22, and a mounting bracket,
generally indicated by the numeral 54, attached to building surface
24 in which clips 52 are selectively secured. In one or more
embodiments, mounting bracket 54 includes a pair of planar surfaces
56 to facilitate attachment to building surface 24, as best seen in
FIG. 4. A fastener 58 passes through each planar surface 56 and
into building surface 24 to secure mounting bracket 54 in a desired
location. In at least one embodiment, fasteners 58 are self-tapping
screws that require no pre-drilling of either mounting bracket 54
or building surface 24. Shims 59 may be provided between mounting
bracket 54 building surface 24 to accommodate for the
irregularities of building surface 24 and to ensure that mounting
bracket 54 is plumb.
[0026] Mounting bracket 54 includes a top channel 60 that receives
a portion of a clip 52 attached to the bottom flange 38 of a wall
panel 22, as will be discussed in greater detail below. Top channel
60 is generally U-shaped, and is displaced outwardly from building
surface 24. Mounting bracket 54 also includes a bottom channel 62
that is positioned below top channel 60, and which is also
displaced outwardly from building surface 24. Bottom channel 62,
like top channel 60, is generally U-shaped and is adapted to
receive a portion of a clip 52 attached to the top flange 36 of a
wall panel 22. In one or more embodiments, bottom channel 62 may
include a protrusion 64 within the U-shaped channel extending
toward building surface 24 on the upper end of the channel.
Protrusion 64 helps to maintain clip 52 within bottom channel 62,
as will be discussed hereinafter.
[0027] In one or more embodiments, clip 52 may be between
approximately 0.5 and 5.0 inches wide, in other embodiments clip 52
may be between approximately 2.0 and 4.0 inches wide, and in a
preferred embodiment clip 52 may be approximately 3.0 inches wide.
In one or more embodiments, a right-angled portion, generally
indicated by the numeral 66, of clip 52, having a first section 67
and a second section 69, rests in the corner created by top flange
36 and body portion 27 of wall panel 22, as best seen in FIG. 3.
First section 67 is proximate flange 36, and second section 69 is
proximate body portion 27. It should be appreciated that
right-angled portion 66 of a clip 52 may also be positioned in the
corners created by the intersection of body portion 27 with bottom
flange 38, left side flange 40, or right side flange 42, with
second section 69 of right-angled portion 66 proximate body portion
27 regardless of the location of clip 52. The pairing of
right-angled portions 66 and the corners of wall panels 22 help to
maintain clip 52 in the proper position and provide additional
strength to wall panel system 20. In one or more embodiments, and
as seen in FIGS. 2 and 3, second section 69 of right-angled portion
66 of clip 52 may also include a displaced portion 71 that is
off-set from the plane of second section 69 in a direction away
from body portion 27. Displaced portion 71 provides a gap 73
between body portion 27 and second section 69.
[0028] In at least one embodiment, clip 52 further includes a slot
68 (FIG. 3) adjacent to the end of flange 36, or one or several of
the other flanges. Slot 68 faces outwardly from wall panel 22 and
is adapted to optionally receive a spline 70 therein, as will be
discussed in greater detail hereinafter. Clip 52 further includes a
projection 72 (FIG. 3) extending away from wall panel 22 and
terminating at a bracket engaging element, generally indicated by
the numeral 74, at its end. Bracket engaging element 74 is oriented
so that it is substantially parallel to body portion 27 of wall
panel 22, and has a first shoe portion 76 on one side of projection
72 extending toward the interior of wall panel 22, and a second
shoe portion 78 on the other side of projection 72 extending
outwardly from wall panel 22. In one or more embodiments, first
shoe portion 76 includes a protrusion 80.
[0029] In one or more embodiments, clip 52 may be attached to wall
panel 22 by an adhesive system, which, when cured, provides an
adhesive layer 65 between clip 52 and wall panel 22. In other
words, adhesive layer 65 bonds clip 52, or at least a portion
thereof, to wall panel 22, or at least a portion thereof. In one or
more embodiments, adhesive layer 65 may be interposed between the
first and second sections 67 and 69 of right-angled portion 66 of
clip 52 and the corner of wall panel 22, thereby securing both
surfaces of right angled portion 66 to wall panel 22. Specifically,
adhesive layer 65 may secure first section 67 to flange 36 and
second section 69 to body portion 27. By utilizing adhesive on both
surfaces of right-angled portion 66 of clip 52, it is possible for
an adhesive to overcome the shear moment acting upon the clip 52 so
long as an appropriate adhesive is used that provides the desired
mechanical properties. In one or more embodiments, adhesive layer
65 may also fill gap 73 between displaced portion 71 of second
section 69 and body portion 27, providing increased resistance to
the shear forces acting upon clip 52.
[0030] In one or more embodiments, the adhesive system includes an
acrylic adhesive, which may be referred to simply as an adhesive.
Uncured acrylic adhesives include a monomer that contains one or
more reactive acrylate groups. For example, the acrylic adhesive
may include acrylate or methacrylate monomer. Examples of
methacrylate monomers include ethyl acrylate, butyl acrylate, and
methyl methacrylate. In one or more embodiments, the uncured
acrylic adhesive may include one or more co-monomers that are
capable of reacting with the acrylate monomer to form a copolymer.
Examples of co-monomers include styrene and unsaturated rubber.
Examples of commercially available acrylic adhesives include
Lord.RTM. 403, 406, and 410, available from Lord Corporation.
[0031] In one or more embodiments, other components of the adhesive
system include an accelerator. Accelerators include mix-in
curatives that promote faster cure times or curing of the adhesive
at room temperature. In one or more embodiments, the accelerator
includes an epoxy resin, diisobutyl phthalate, and benzoyl
peroxide. Examples of commercially available accelerators for
acrylic adhesives includes Lord.RTM. 19 and 19GB.
[0032] In one or more embodiments, the adhesive system may be
applied to the substrate (wall panel 22 or clip 52) as a two part
system (e.g., The acrylic adhesive as one component and the
accelerator as another component). This application method is well
known in the art, and involves the application of the two
components from separate containers, allowing the two components of
the adhesive system to react or interact with each other, and then
introducing the mixture to the surface to be bonded.
[0033] The ratio of adhesive to accelerator may vary. In one or
more embodiments, the mix ratio of adhesive to accelerator by
weight may be from about 2:1 to about 4:1, in other embodiments
from about 2.5:1 to about 3.5:1, and in other embodiments from
about 2.7:1 to about 3.3:1. An exothermic reaction may produce heat
buildup upon mixing and curing that may begin immediately. In one
or more embodiments, handling strength is achieved at room
temperature within about 4 to about 60 minutes from mixing. As will
be understood by those skilled in the art, handling strength refers
to the strength required for transportion or for following
operations of the bonded article without disturbing the bond
created by the adhesive. In one or more embodiments, substantially
complete cure is achieved within about 24 hours at room
temperature.
[0034] In one or more embodiments, the surfaces to be bonded may be
pre-treated to remove grease, oxides, or other contaminants.
Pretreatment of the surfaces may include any known method of
preparing a surface for adhesive bonding, including cleaning the
surface with high pressure air, wiping the surface down with water,
or the use of quick vaporizing solvents.
[0035] In one or more embodiments, effective adhesives are
characterized by a cured tensile strength at break (ASTM D638) of
at least 25 MPa, in other embodiments at least 28 MPa, in other
embodiments at least 30 MPa, and in other embodiments at least 32
MPa.
[0036] In one or more embodiments, effective adhesives are
characterized by a cured elongation at break (ASTM D638) of at
least 25%, in other embodiments at least 27%, in other embodiments
at least 29%, and in other embodiments at least 30%.
[0037] In one or more embodiments, effective adhesives are
characterized by a cured Young's Modulus (ASTM D638) of at least
800 MPa, in other embodiments at least 840 MPa, in other
embodiments at least 880 MPa, and in other embodiments at least 895
MPa.
[0038] In one or more embodiments, effective adhesives are
characterized by a cured Glass Transition Temperature (ASTM
E1640-99) of at least 68.degree. C., in other embodiments at least
70.degree. C., in other embodiments at least 72.degree. C., and in
other embodiments from about 68 to about 80.degree. C.
[0039] In one or more embodiments, the bond performance of adhesive
layer 65 may be characterized by a lap shear at room temperature
(ASTM D1002; Failure Mode C; 1.0''.times.0.5'' bond area; 0.010''
film thickness; 24 hr at room temperature cure; aluminum to
aluminum) of at least 15 MPa, in other embodiments at least 17 MPa,
in other embodiments 17.5 MPa, and in other embodiments 18.0
MPa.
[0040] In one or more embodiments, the bond performance of adhesive
layer 65 may be characterized by a lap shear at hot strength
[82.degree. C.] (ASTM D1002; Failure Mode TLC; 1.0''.times.0.5''
bond area; 0.010'' film thickness; 24 hr at room temperature cure;
aluminum to aluminum) of at least 10 MPa, in other embodiments at
least 12 MPa, in other embodiments 13 MPa, and in other embodiments
13.5 MPa.
[0041] In one or more embodiments, the bond performance of adhesive
layer 65 may be characterized by a lap shear after 500 hours salt
spray exposure (ASTM D1002; Failure Mode TLC; 1.0''.times.0.5''
bond area; 0.010'' film thickness; 24 hr at room temperature cure
aluminum to aluminum) of at least 15 MPa, in other embodiments at
least 17 MPa, in other embodiments 17.5 MPa, and in other
embodiments 18 MPa.
[0042] In one or more embodiments, the bond performance of adhesive
layer 65 may be characterized by a lap shear after 14 days at
38.degree. C. and 100% RH (ASTM D1002; Failure Mode C;
1.0''.times.0.5'' bond area; 0.010'' film thickness; 24 hr at room
temperature cure; aluminum to aluminum) of at least 16 MPa, in
other embodiments at least 18 MPa, in other embodiments 19 MPa, and
in other embodiments 20 MPa.
[0043] In one or more embodiments, the bond performance of adhesive
layer 65 may be characterized by a lap shear at -34.degree. C.
(ASTM D1002; Failure Mode C; 1.0''.times.0.5'' bond area; 0.010''
film thickness; 24 hr at room temperature cure; aluminum to
aluminum) of at least 14 MPa, in other embodiments at least 15.5
MPa, in other embodiments 16.5 MPa, and in other embodiments 17
MPa.
[0044] In one or more embodiments, the bond performance of adhesive
layer 65 may be characterized by a T-peel (ASTM D1876; Failure Mode
C; 1.0''.times.3.0'' bond area; 0.010 film thickness; 72 hr at room
temperature cure; aluminum to aluminum) of at least 3.0 N/mm, in
other embodiments at least 3.5 N/mm, in other embodiments at least
4.0 N/mm, and in other embodiments at least 4.3 N/mm.
[0045] With reference back to FIG. 2, the interrelation of mounting
bracket 54 and clips 52 can be seen. A clip 52 secured to a bottom
flange 38 of upper wall panel 22 is engaged with top channel 60 of
mounting bracket 54. More specifically, second shoe portion 78
rests within top channel 60 and supports and anchors wall panel 22.
Another clip 52 secured to a top flange 36 of lower wall panel 22
is engaged with bottom channel 62 of mounting bracket 54. More
particularly, protrusion 80 of first shoe portion 76 of engaging
element 74 snaps into place over protrusion 64 in bottom channel
62, thereby providing secure attachment of clip 52 to mounting
bracket 54.
[0046] As is apparent from the drawings, a single mounting bracket
54 can provide mounting channels for the bottom of one wall panel
22 and the top of another wall panel 22. It should be appreciated
that in one or more embodiments clips 52 and mounting brackets 54
may also be provided on the vertical flanges of wall panels 22.
Additional clips may be particularly useful, and may be necessary,
in cases where wall panel 22 has a significant height and therefore
requires additional support along its vertical flanges. Clips 52
are interchangeable within attachment system 50, meaning that a
clip 52 may be used on top flange 36, bottom flange 38, or vertical
flanges.
[0047] A fastener 84, as shown in FIG. 2, passes through bottom
channel 62 and first shoe portion 62 of engaging element 74 to
secure clip 52 to mounting bracket 54. However, in a preferred
embodiment of the invention, fastener 84 is used in only a single
clip 52 or, optionally, a pair of clips 52 positioned near the
center of flange 36 or flange 38, while the remaining clips 52
along the flanges are not secured to mounting bracket 54 by a
fastener. Such an arrangement secures wall panel 22 in place within
wall panel system 20, while also allowing for thermal expansion and
contraction of wall panel 22 in multiple directions from the center
of the flanges. In this way wall panels 22 may be securely attached
to building surface 24 without inhibiting the natural thermal
expansion and contraction cycles of wall panel system 20.
[0048] An exemplary clip arrangement is shown in FIG. 5, where a
wall panel 22 is depicted having five clips 52 along a top flange
36, and one clip positioned on each of left side flange 40 and
right side flange 42. Center clip 90 on top flange 36 is attached
to a mounting bracket 54 by a fastener 84, as best seen in FIG. 2.
The additional clips 91, 92, 93, and 94 on top flange 36 are not
attached to mounting bracket 54 by a fastener 84 so that they are
free to slide within bottom channel 62. Thus, wall panel 22 is
maintained in a static location, while being free to expand in both
the left and right directions during thermal cycling. In addition,
this exemplary clip arrangement includes clips 96 and 95 on left
side flange 40 and right side flange 42, respectively, to further
secure wall panel 22 to building surface 24. Clips 95 and 96 may be
secured to mounting brackets 54 in the same manner as clip 90, and
as shown in FIG. 2.
[0049] As can be seen in FIG. 2, and as previously mentioned, one
or more embodiments of attachment system 50 may include a spline 70
positioned within opposing slots 68. Spline 70 is a narrow strip
that may be made of metal, plastic, a composite material, or any
other suitable, weather resistant material. Spline 70 acts to cover
and to at least partially seal gap 25 between adjacent wall panels
22. Spline 70 is sized to fit slidingly within opposing slots 68
such that it may be inserted after placement of the panels, and
also to allow for thermal expansion of wall panels 22. In at least
one embodiment, splines 70 run horizontally within gaps 25 between
adjacent wall panels 22, as well as vertically within gaps 25
between adjacent wall panels 22. Integration of slots 68 for
receiving splines 70 into clips 52 is advantageous because it
reduces the number of parts in wall panel system 20 and makes
installation simple and more efficient.
[0050] Various modifications and alterations that do not depart
from the scope and spirit of this invention will become apparent to
those skilled in the art. This invention is not to be duly limited
to the illustrative embodiments set forth herein.
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