Precast panel mounting system
A rigid elongate mounting bracket has an embedment portion and an extension portion. The extension portion has a fastener opening and abutment means. When cast into a precast panel in an appropriate angular orientation adjacent to an edge of a cladding panel, the extension portion projects rearwardly and laterally away from the rear face of the panel end such that the end of the extension portion is disposed at a distance away from the panel's rear face corresponding to a desired air space, and the abutment means is substantially aligned with the panel's rear face. Each panel preferably has at least two brackets spaced along its upper edge and two more along its lower edge. A first panel may be mounted to a supporting structure using fasteners driven through the fastener openings of the upper brackets. A second panel may then be positioned with its lower brackets extending downward behind the first panel, with the abutment means of the second panel's lower brackets engaging the rear face of the first panel, such that the lower end of the second panel is laterally stabilized by the first panel, with a uniform air space being formed between the supporting structure and the panels' rear faces.
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 INVENTIONPrecast 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 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 Feb. 3, 2004, and similarly in U.S. Pat. No. 6,253,515 issued to Kuelker on Jul. 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 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 (Wünsch), filed Mar. 17, 1982;
- French Patent Application No. 82 14147 (Michelet et al.), filed Aug. 16, 1982;
- U.S. Pat. No. 4,553,366 (Guerin), issued Nov. 19, 1985; and
- European Patent Application No. 89115208.4 (Isele), filed Aug. 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.
BRIEF SUMMARY OF THE INVENTIONIn 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 connection between the bottom of the second panel and the supporting structure.
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.
- (a) a rigid, elongate main body having an outer side, an inner side, and two longitudinal edges, said main body also defining:
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: - (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.
- (a) a rigid, elongate main body having an outer side, an inner side, and two longitudinal edges, said main body also defining:
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 DRAWINGSEmbodiments of the invention will now be described with reference to the accompanying figures, in which numerical references denote like parts, and in which:
Referring to
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
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
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.
In a typical arrangement, as shown in
Brackets 10 may be positioned in a variety of patterns along longitudinal edges 56. In the preferred configuration shown in
The specific bracket layouts shown in
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
At a typical horizontal joint as shown in
Particular advantages of the present invention may be readily appreciated from the foregoing discussion of
Because as few as two brackets 10 can be used along each longitudinal edge 56 of a typical cladding panel 50 (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
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.
The installation of top panel 50T may be facilitated by folding angled lips 16T of brackets 10T upward as indicated in
Persons skilled in the art will readily appreciate that other methods for mounting top panel 50T are possible. For example, top panel 50T 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.
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 10B are connected thereto), the weight of bottom panel 50B induces a counterclockwise moment (as viewed in
After bottom panels 50B have been mounted, additional panels may be mounted thereabove in the usual manner, as shown in
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 panel 50B will depend on the specific architectural details of the structure in question.
In the preferred embodiment shown in
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
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
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, 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.
Claims
1. 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.
2. The mounting bracket of claim 1 wherein the extension portion has a primary fastener opening near its inner end.
3. The mounting bracket of claim 2 wherein the extension portion has an auxiliary fastener opening positioned away from the primary fastener opening and toward the embedment section.
4. The mounting bracket of claim 1, further comprising an auxiliary anchorage element associated with the embedment portion.
5. The mounting bracket of claim 1 wherein the bracket is formed from sheet metal.
6. The mounting bracket of claim 5 wherein the abutment means is a punch-formed angled tab.
7. The mounting bracket of claim 4 wherein the bracket is formed from sheet metal and the auxiliary anchorage element main body is a punch-formed anchor tab.
8. The mounting bracket of claim 1, further comprising a stiffening flange extending from one of the longitudinal edges of the main body
9. The mounting bracket of claim 5 wherein the abutment means is formed integrally with the main body.
10. The mounting bracket of claim 1 wherein the bracket is formed from metal wire.
11. 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:
- (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.
12. The precast panel of claim 11, wherein each mounting bracket has at least one fastener opening near the inner end of its extension portion.
13. The precast panel of claim 11, having at least two mounting brackets embedded in spaced-apart relation adjacent its upper edge and at least two mounting brackets embedded in spaced-apart relation adjacent its lower edge, wherein each mounting bracket embedded adjacent the upper panel edge has at least one fastener opening near the inner end of its extension portion.
14. The precast panel of claim 11 wherein the extension portion of each mounting bracket has a primary fastener opening near its inner end.
15. The precast panel of claim 14 wherein the extension portion of each mounting bracket has an auxiliary fastener opening positioned away from the primary fastener opening and toward the embedment section.
16. The precast panel of claim 11 wherein each mounting bracket further comprises an auxiliary anchorage element associated with the embedment portion.
17. The precast panel of claim 11 wherein each mounting bracket is formed from sheet metal.
18. The precast panel of claim 17 wherein the abutment means of each mounting bracket is a punch-formed angled tab.
19. The precast panel of claim 16 wherein each mounting bracket is formed from sheet metal and the auxiliary anchorage element is a punch-formed anchor tab.
20. The precast panel of claim 11 wherein each mounting bracket further comprises a stiffening flange extending from one of the longitudinal edges of the main body
21. The precast panel of claim 17 wherein the abutment means of each mounting bracket is formed integrally with the main body.
22. The precast panel of claim 11 wherein each mounting bracket is formed from metal wire.
Type: Application
Filed: Nov 25, 2005
Publication Date: May 31, 2007
Inventor: Peter Kuelker (Calgary)
Application Number: 11/286,332
International Classification: E04C 3/16 (20060101);