US20090282777A1 - Angle joint for sandwich panels and method of fabricating same - Google Patents

Abstract

An angle joint between two sandwich panels, wherein the sandwich panels each have a first outer layer and a second outer layer spaced from the first outer layer by a panel core, and an angle edge including an edge portion of the panel core and an edge portion of the first outer layer. The joint has an interface between the panel cores and the interface has an entranceway at an inner corner comprised of the edge portions of the first outer layers. A cavity in the panel cores is defined by a portion of the second outer layers and a portion of each panel core. The cavity spans across a second entranceway to the interface between panel cores. Bonding material applied in the cavity and at the inner corner connects the sandwich panels together in a manner that maintains an area of dead air space at the interface to inhibit or to reduce thermal transmissions across the joint.

Description

TECHNICAL FIELD OF THE INVENTION
• The present invention relates generally to constructing buildings, and more particularly, to connecting adjacent sandwich panels with an angle joint that reduces or minimizes thermal bridging across the joint.
DESCRIPTION OF THE RELATED ART
• There is an increasing global demand for lower cost buildings such as houses, warehouses and office space. The demand for lower cost buildings is particularly strong in developing countries where economic resources may be limited and natural resources and raw materials may be scarce. For example, in areas of the Middle East or Africa, conventional building materials such as cement, brick, wood or steel may not be readily available or, if available, may be very expensive. In other areas of the world, poverty may make it too costly for people to build houses or other buildings with conventional materials.
• The demand for lower-cost housing also is high in areas afflicted by war or natural disasters, such as hurricanes, tornadoes, floods, and the like. These devastating events often lead to widespread destruction of large numbers of buildings and houses, especially when they occur in densely populated regions. The rebuilding of areas affected by these events can cause substantial strain on the supply chain for raw materials, making them difficult or even impossible to obtain. Furthermore, natural disasters often recur and affect the same areas. If a destroyed building is rebuilt using the same conventional materials, it stands to reason that the building may be destroyed or damaged again during a similar event.
• It is generally desirable to increase speed of construction and to minimize construction costs. Prefabricated or preassembled components can streamline production and reduce both the time and the cost of building construction. Prefabricated buildings, however, are made from conventional materials that may be scarce or expensive to obtain. Thus, there exists a need for alternative materials and techniques for constructing buildings that use advanced material technologies to increase the speed of construction and to reduce or to lower ownership costs.
SUMMARY
• The present invention provides an alternative to conventional construction materials and techniques. Buildings, such as houses, commercial buildings, warehouses, or other structures can be constructed by composite sandwich panels (also referred to as “sandwich panels” or “composite panels”), which have an insulative core and one or more outer layers. The buildings can be constructed by gluing several sandwich panels together, and usually traditional fasteners, such as screws, rivets, nails, etc., are not needed for such connections. Generally, composite sandwich panels offer a greater strength to weight ratio over traditional materials that are used by the building industry. Because they weigh less than traditional building materials, the handling and transport of composite sandwich panels is generally less expensive. The composite sandwich panels are generally as strong as, or stronger than, traditional materials including wood-based and steel-based structural insulation panels, while being lighter in weight. The composite sandwich panels also can be used to produce light-weight buildings, such as floating houses or other light-weight structures.
• Sandwich panels generally are more elastic or flexible than conventional materials such as wood, concrete, steel or brick and, therefore, monolithic buildings made from sandwich panels are more durable than buildings made from conventional materials. For example, sandwich panels also may be non-flammable, waterproof, very strong and durable, and in some cases able to resist hurricane-force winds (up to 300 Kph (kilometers per hour) or more). The sandwich panels also may be resistant to the detrimental effects of algae, fungicides, water, and osmosis. As a result, buildings constructed from sandwich panels may be better able to withstand earthquakes, floods, tornadoes, hurricanes, fires and other natural disasters than buildings constructed from conventional materials.
• Two construction elements, e.g., two composite sandwich panels, can be connected together by an angle joint. It is generally desirable to avoid creating a thermal bridge across the joint from one side of the construction elements to the other. Generally speaking, a thermal bridge is a pathway for bypassing an insulation system to allow heat to pass from one side of the wall to the other. Thermal bridges are particularly undesirable for external walls of a structure where temperatures may vary greatly from the outside of the structure to the inside of the structure.
• As described in more detail below, two sandwich panels can be connected together to minimize or to reduce thermal bridging across the joint between the panels, by cutting and removing an edge portion of the sandwich panels, e.g., by a miter cut. The angle joint is formed by aligning the edges of the panel cores such that the core of one panel is in physical contact with the core of the adjacent panel. A cavity is formed by removing a portion of the sandwich panel cores. A pathway to the cavity is formed, for example, by making a hole through at least one of the outer layers of the sandwich panels or by removing a strip of the outer layer near the edge of the panel to form a gap between the edges of the outer layers of the panels. Bonding material is injected through the pathway and into the cavity to seal an entranceway to the area of contact between the panel cores and to secure or to bond the panels to one another.
• The resulting angle joint minimizes, reduces or eliminates thermal transmissions from one side of the panel to the other side of the panel.
• According to one aspect of the invention, an angle joint between a first sandwich panel and a second sandwich panel, has a first sandwich panel having a first outer layer and a second outer layer spaced from the first outer layer by a panel core, and an angle edge comprised of an edge portion of the panel core and an edge portion of the first outer layer; a second sandwich panel having a first outer layer and a second outer layer spaced from the first outer layer by a panel core, and an angle edge comprised of an edge portion of the panel core and an edge portion of the first outer layer, wherein the angle edges of the sandwich panels are in contact with one another at an interface between the panel cores, an entranceway to the interface between the panel cores at an inner corner comprised of the edge portions of the first outer layers; a cavity in the panel cores, the cavity defined by a portion of the second outer layers and a portion of each panel core, the cavity spanning across a second entranceway to the interface between panel cores; and bonding material in the cavity and at the inner corner to connect the first sandwich panel to the second sandwich panel.
• According to another aspect of the angle joint, the joint further includes a pathway through at least one of the second outer layers to the cavity and through which the bonding material is injectable.
• According to another aspect of the angle joint, the pathway is a gap between an edge of the second outer layer of the first sandwich panel and an edge of the second outer layer of the second sandwich panel.
• According to another aspect of the angle joint, the joint includes an outer corner comprised of bonding material between the edges of the second outer layers.
• According to another aspect of the angle joint, the pathway is a hole formed in the second outer layer of at least one of the sandwich panels.
• According to another aspect of the angle joint, the angle edge of each sandwich panel further includes an edge portion of the second outer layer of the sandwich panel, and the joint further comprises an outer corner comprised of the edge portions of the second outer layer of each sandwich panel.
• According to another aspect of the angle joint, the cavity extends along a length of the second outer layer of each sandwich panel, wherein the length of the cavity along the second outer layer is at least seven times greater than a thickness of the second outer layer.
• According to another aspect of the angle joint, the cavity extends perpendicularly from the second outer layer of each sandwich panel along a length of the panel core, wherein the length of the cavity extending perpendicularly into the panel core is at least seven times greater than the thickness of the second outer layer.
• According to another aspect of the angle joint, the bonding material in the cavity and at the inner corner seals entranceway to the interface between the panel cores, and the interface is dead air space.
• According to another aspect of the angle joint, the interface between the sandwich panel cores inhibits thermal transmissions across the joint from the first outer layer to the second outer layer.
• According to another aspect of the angle joint, the bonding material at the inner corner has a radius.
• According to another aspect of the angle joint, the panel cores are comprised of insulating materials and the first and second outer layers are comprised of composite materials.
• According to another aspect of the invention, a method of joining two sandwich panels in a non-linear orientation, the sandwich panels having a core, an outer layer covering at least one surface of the core, an angle edge and a cavity, the method includes placing the panels edge to edge to form an interface in an area between the panel cores and a combined cavity, and applying bonding material in the cavity to hold the panels together and to block thermal transmissions across the joint.
• According to another aspect of the method, the applying step further includes injecting bonding material into the cavity through a gap in the edges of the outer layers of the sandwich panels.
• According to another aspect of the method, the applying step further includes injecting bonding material into the cavity through at least one hole in at least one of the outer layers.
• According to another aspect of the method, the sandwich panels have a second outer layer covering at least one surface of the core, and wherein the placing step further includes placing the second outer layers edge to edge to form an inner corner of the joint.
• According to another aspect of the method, the method includes applying bonding material at the inner corner of the joint.
• According to another aspect of the invention, a method of joining two sandwich panels with an angle joint, wherein each sandwich panel has a first outer layer and a second outer layer spaced from the first outer layer by a panel core, the method including removing an edge portion of each panel to form an angle edge, the angle edge comprising a portion of the panel core and an edge of the first outer layer; placing the angle edges in contact with one another, such that there is an interface between the panel cores and the edges of the first outer layers are in contact with one another to form an inner corner and an entranceway to the interface; forming a cavity by removing a portion of the panel core, the cavity defined by a portion of the second outer layer of each sandwich panel and a portion of the core; filling the cavity with a bonding material that spans across a second entranceway to the interface; and applying bonding material that spans across the entranceway at the inner corner.
• According to another aspect of the method, the step of forming the cavity includes removing a portion of the core near the second outer layer of each sandwich panel and a portion of the panel core extending perpendicularly from the second outer layer of each sandwich panel.
• According to another aspect of the method, the step of forming a cavity includes removing a portion of the panel core near the second outer layer of each sandwich panel that has a length that is at least seven times a thickness of the second outer layer.
• According to another aspect of the method, the step of forming a cavity includes removing a portion of the panel core extending perpendicularly from the second outer layer of each sandwich panel that has a length that is at least seven times the thickness of the second outer layer.
• According to another aspect of the method, the method includes the step of forming a pathway to the cavity by removing a portion of the second outer layer of at least one of the sandwich panels.
• According to another aspect of the method, the method includes removing a portion from the second outer layer of at least one of the sandwich panels to form a hole.
• According to another aspect of the method, the step of forming a pathway includes removing a strip of the second outer layer from each of the sandwich panels to form an edge of the second outer layer of each sandwich panel, wherein the edges of the second layers are spaced from one another to form a gap.
• According to another aspect of the method, the method further includes spreading bonding material between the edges of the second outer layers to form an outer corner.
• According to another aspect of the method, the method further includes installing the sandwich panels are as part of a monolithic building.
• According to another aspect of the invention, a sandwich panel includes a first outer layer and a second outer layer, the outer layers separated from one another by an insulative core; an angle edge comprised of a portion of the insulative core and a portion of the first outer layer; a cavity in the insulative core, the cavity defined by a portion of the second outer layer and a portion of the core; and a pathway through the second outer layer to the cavity through which a bonding material may be injected to form an angle joint between the sandwich panel and an adjacent construction element, wherein the insulative core inhibits thermal transfer across the joint from the first outer layer to the second outer layer.
• According to another aspect of the invention, a method of forming a sandwich panel including mounting a first outer layer to a core; mounting a second outer layer to the core; forming an angle edge of the sandwich panel, the angle edge comprising a portion of the first outer layer and a portion of the core; forming a cavity between a portion of the second outer layer and a portion of the core; and providing access to the cavity through the second outer layer with a pathway through which bonding material is injectable to form a joint between the angle edge of the sandwich panel and a construction element in a manner that inhibits thermal transmissions across the joint.
• These and further features of the present invention will be apparent with reference to the following description and attached drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the ways in which the principles of the invention may be employed, but it is understood that the invention is not limited correspondingly in scope. Rather, the invention includes all changes, modifications and equivalents coming within the spirit and terms of the claims appended hereto.
• It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.
• Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with, or instead of, the features of the other embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is an environmental view of an exemplary monolithic structure built from composite materials.
• FIG. 2 is an isometric view of two sandwich panels connected by an angle joint.
• FIG. 3 is an isometric view of an exemplary sandwich panel.
• FIG. 4 is a fragmentary schematic sectional top view of an edge portion of an exemplary sandwich panel.
• FIG. 5 is a fragmentary schematic sectional top view of an embodiment of an angle joint between two sandwich panels.
• FIG. 6 is a fragmentary schematic sectional top view of an embodiment of an angle joint between two sandwich panels.
• FIG. 7 is a fragmentary schematic sectional top view of an edge portion of a sandwich panel.
• FIG. 8 is a fragmentary schematic sectional top view of an embodiment of an angle joint between two sandwich panels.
• FIG. 9 is a fragmentary schematic sectional top view of an embodiment of an angle joint between two sandwich panels.
DETAILED DESCRIPTION OF EMBODIMENTS
• In the detailed description that follows, like components have been given the same reference numerals regardless of whether they are shown in different embodiments of the invention. To illustrate the present invention in a clear and concise manner, the drawings may not necessarily be to scale and certain features may be shown in somewhat schematic form. Certain terminology is used herein to describe the different embodiments of the invention. Such terminology is used only for convenience when referring to the figures. For example, “upward,” “downward,” “above,” or “below” merely describe directions in the configurations shown in the figures. Similarly, the terms “interior” and exterior” or “inner” and “outer” are used for convenience to describe the orientation of the components in the figures. The components can be oriented in any direction and the terminology should therefore be interpreted to include such variations. The dimensions provided herein are exemplary in nature and are not intended to be limiting in nature. Furthermore, while described primarily with respect to house construction, it will be appreciated that all of the concepts described herein are equally applicable to the construction of any type of structure or building, such as warehouses, commercial buildings, factories, apartments, etc.
• The structures described herein are built with composite materials, such as composite sandwich panels. Sandwich panels, which may be formed from synthetic or natural materials, provide a light-weight and potentially less expensive alternative to conventional raw materials, e.g., wood, concrete, metal, etc. If desired, natural materials may be used in the sandwich panels, as described in more detail below. The sandwich panels may be connected or joined together with a high-strength bonding material, such as epoxy or glue, and conventional fasteners, such as nails and screws, are not usually needed. The result is a strong and durable monolithic (e.g., single unit) structure, as is described further below.
• Referring toFIG. 1, an exemplarymonolithic structure10, for example, a house, is built from a number of sandwich panels. As illustrated, thehouse10 includes a number of sandwich panels, for example, twosandwich panels11,12 connected with a straight joint13 to form afront wall10fand twosandwich panels14,15 connected with a straight joint16 to form aside wall10s. Thefront wall10fandside wall10sare connected to one another by an angle joint20. Thehouse10 has another side wall, a rear wall, and possibly other walls, which may not be shown, and may be, for example, on the interior or exterior of the house. Also, while illustrated as having walls that are formed from two sandwich panels, it will be appreciated that the respective walls may be formed from a single sandwich panel or may include a number of sandwich panels.
• It generally is desirable to reduce or to minimize thermal transmissions through the walls of thehouse10, for example, to improve energy efficiency and to reduce heating or electrical costs. The angle joint20, therefore, is formed to minimize thermal transmissions across the joint, for example, from an exterior10eof thehouse10 to an interior10iof thehouse10.
• An exemplary embodiment of the angle joint20 is shown inFIG. 2. Twosandwich panels12,14 are connected to one another in an angled or non-linear orientation to form the angle joint20. Thefirst sandwich panel12 has twoouter layers21,22 separated by a generally planar,insulative core23. Theouter layers21,22 generally cover at least one surface of thecore23. Similarly, thesecond sandwich panel14 has twoouter layers24,25 separated by a generally planar,insulative core26. Theouter layers22,24 generally cover at least one surface of thecore26. Thesandwich panels12,14 each have respective angle edges23a,26athat abut one another at the joint20. The angle edges23a,26aabut or contact one another to create aninterface30.
• The joint20 has aninner corner32 and anouter corner33. Theinner corner32 is formed by the junction of theouter layers22,25 of thesandwich panels12,14. Theouter corner33 is formed by the junction of theouter layers21,24 of thesandwich panels12,14. The terms “inner” and “outer” are used herein for convenience to describe the several embodiments or aspects of the angle joint. The joint20 is not limited to a joint separating the exterior10eand interior10iof the house, and the joint may be, for example, located at any area of the house, including between walls solely on the interior of the house.
• Theinterface30 extends between thepanel cores23,26 between theinner corner32 to theouter corner33. Theinterface30 has an entranceway or edge30anear theinner corner32, and another entranceway or edge30bnear theouter corner33.
• Theentranceways30a,30bto theinterface30 are sealed by bondingmaterial34,35. The entranceway30ais sealed by bondingmaterial34 spread or applied at theinner corner32, and the entranceway30bis sealed by bondingmaterial35 spread or applied at theouter corner33. Thebonding material34,35 spans across theedges30a,30bto create an area of dead air space at theinterface30 between theedges23a,26aof thepanel cores23,26. Thebonding material34,35 also is in contact with the outer layers of each of the panels and securely holds or connects thesandwich panels12,14 to one another. The resulting joint20 inhibits or reduces thermal transmissions across the joint20.
• Referring briefly toFIG. 3, an exemplary sandwich panel is shown, e.g., thesandwich panel14. Thesandwich panel14 includes twoouter layers24,25 separated by acore26. Thecore26 is formed from a generally planar, insulative material. Theouter layers24,25 are rigidly bonded or adhered to the core26 with bonding material. Further details of the sandwich panel are presented below. Thesandwich panels12,14 used in the angle joint20 are modified or prepared as is described with respect to the several embodiments below to form a joint that minimizes or reduces thermal bridging across the joint.
• FIG. 4 illustrates the preparation of anedge40 of the sandwich panel, e.g.,sandwich panel14, prior to connection with another sandwich panel, e.g.,sandwich panel12, which may be prepared in a similar manner.FIGS. 5 and 6 illustrate the angle joint20 formed by connecting thesandwich panels12,14 to one another.
• Referring initially toFIG. 4, theedge40 of thesandwich panel14 is modified by cutting and removing aportion41 of thepanel14. Theedge40 is cut at an angle, e.g., by a miter cut. The miter cut forms a new,angle edge26ato thesandwich panel14. The miter cut also creates anew edge24atoouter layer24 and anew edge25atoouter layer25.
• The angle of theedge40 may be modified based upon the desired angle of the resulting joint20 when thesandwich panels12,14 are connected to one another. For example, if a 90-degree resultant angle is desired, then theedge26ais cut at an angle α (alpha) that is 45-degrees. Similarly, theedge23aof theadjacent sandwich panel12 would be cut at a 45-degree angle, such that when theedges23a,26aare aligned with one another, a 90-degree joint is formed. It will be appreciated that theedges22a,26amay be cut at any desired angle to form an angle joint20 that is larger than 90-degrees (e.g., obtuse) or smaller than 90-degrees (e.g., acute).
• Continuing to refer toFIG. 4, aportion42 of theouter layer24 is cut or removed from thepanel14. The removal of theportion42 creates anew edge24bofouter layer24. Theportion42 may be, for example, a strip of theouter layer24 that may be removed by cutting theouter layer24 with a blade or other cutting implement. Theportion42 removed from theouter layer24 may be one or more millimeters in length and may be, for example, about 1-10 mm (millimeters), or larger. Theportion42 may include theedge24aof theouter layer24 that was formed by the miter cut.
• Aportion43 of thecore26 is removed from thepanel14 near thenew edge24bto form acavity44. Thecavity44 extends generally along the inner surface of theouter layer24, as indicated generally by dimension “A.” Thecavity44 also extends generally perpendicular from or normal to theouter layer24 and towards the center of the core26, as indicated generally by dimension “B.” Thecavity44, therefore, is defined by a portion of theouter layer24 near theedge24aand asloped edge45 of the core26, which is formed when theportion43 is removed.
• Thecavity44 may be of another size or proportion and/or shape. For example, more core material may be removed for larger (e.g., thicker)outer layers24,25 or less core material may be removed for smaller (e.g., thinner)outer layers24,25. It will be appreciated that while thecavity44 is illustrated as triangular in shape, numerous other configurations may be possible. For example, thecavity44 may not be triangular in shape and may be similar to another shape, such as a curved shape, a circular (or partial circular) shape, a rectangular shape or a square shape, etc. It also will be appreciated that thecore26 andouter layers24,25 may be formed or molded in the configuration ofFIG. 4, e.g., during manufacturing the shape of the mold in which thecore26 is formed may form theedge26aand slopededge45, and theouter layer24 may be applied such that a portion of theouter layer42 extends over the area of theportion43 of the core26 to form thecavity44.
• As shown inFIGS. 5 and 6,sandwich panel12 is prepared or shaped in a similar manner tosandwich panel14. The miter cut on the edge ofsandwich panel12 forms anew edge22ato theouter layer22 andnew edge23ato thecore23. A portion of theouter layer21 is removed to form anew edge21b. A portion of the core23, similar to theportion43 removed from the sandwich panel12) also is removed fromsandwich panel14 to form a cavity in thesandwich panel14 that is defined by a portion of theouter layer21 near theedge21bandportion46 of thecore23.
• Referring toFIG. 6, thesandwich panels12,14 are arranged to form theinterface30 between theedges23a,26aof thepanel cores23,26. Theinsulative panel cores23,26 are placed or pressed into contact with one another at theinterface30 such that there is little or no gap between theedges23a,26aof thepanel cores23,26. Theedges22a,25aof theouter layers22,25 are aligned with one another to form theinner corner32, while the respective cavities are aligned with one another to form a combined cavity47 (also referred to as a “cavity”).
• Due to the removal of the portion or strip of theouter layers21,24, theedges21b,24bof theouter layers21,24 are separated from one another to form agap50 at theouter corner33. Thegap50 provides a pathway to thecavity47 through which thebonding material35 may be injected or applied to seal theedge30bof theinterface30. In one embodiment, thegap50 is about 2-20 mm (millimeters) wide. It will be appreciated that a larger orsmaller gap50 may be formed by removing more or less of theouter layers21,24, which would result in theedges21b,24bbeing spaced closer or further apart from one another, as may be desired.
• Continuing to refer toFIG. 6,bonding material34 is applied to theinner corner32 to close theedge30aof theinterface30 near theinner corner32. Thebonding material34 may be shaped or molded to form a round corner having a radius R. The roundedbonding material34 at theinner corner32 directs or distributes the forces over an area and to theouter layers22,25, which may be stronger or more rigid than thepanel cores23,26.
• The length of the radius R may be about 15 mm (millimeters)-40 mm (millimeters) in length. The length of the radius R may be selected based upon the thicknesses of the outer layers, e.g., theouter layers22,25, according to a desired ratio. The desired ratio of the radius R to the thickness of the outer layers may be about seven to one (7:1), or more, e.g., 8:1 or an even larger ratio. For instance if theouter layers22,25 are about 2 mm (millimeters) thick, the radius R would be at least about 14 mm (millimeters), and may be thicker, if desired, or adjusted based upon a desired strength or other factor, such as the strength of the bonding material. In another example, theouter layers22,25 may be 3 mm (millimeters) thick and the radius R is at least about 21 mm (millimeters) or more.
• Bonding material35 also is applied to theouter corner33 by injecting or otherwise applying thebonding material35 through the gap orpathway50 and into thecavity47. Thebonding material35 fills thecavity47 and seals theouter corner33 of the joint20 and seals theinterface30 by spanning across theedge30b. Thebonding material35 also transmits or distributes loads to theouter layers21,24. Thebonding material35 may be molded or shaped to form asmooth edge51 to theouter corner33. The newouter edge51, may be, for example, about 2-20 mm (millimeters) in length, and it will be appreciated that it may be larger or smaller as desired and/or dependent on the size of the portion(s) or strips removed from theouter layers21,24, e.g., portion42 (FIG. 4).
• Thebonding material34,35 may be any suitable bonding material such as epoxy, epoxy resin, glue, cement, adhesive, adhering material or another bonding material (these terms may be used interchangeably and equivalently herein).
• Because there is little or no gap between thepanel cores23,26 at theinterface30, thebonding material34 at theinner corner32 tends not to seep into or through theedge30aand into theinterface30 between theedges23a,26aof thesandwich panel cores23,26. Similarly, thebonding material35 fills thecavity47 but generally tends not to seep into or through theedge30b. Thus, thebonding material34 at theinner corner32 is separate or isolated from thebonding material35 at theouter corner33.
• Thebonding material34,35 maintains theinterface30 to eliminate a direct pathway from one side of the joint (e.g., the inner corner32) to the other side of the joint (e.g., the outer corner33) and maintains theinterface30 as a region of dead air space to achieve a thermal insulating effect that minimizes or reduces thermal transmissions across or through the joint20. Thebonding material34,35 also is applied such that it overlaps the outer layers of thesandwich panels12,14 and holds or connects thepanels12,14 rigidly to one another. The resulting angle joint20, therefore, is a rigid joint that provides a thermal barrier to inhibit, reduce, or eliminate thermal transmissions across the joint20.
• An alternative embodiment is illustrated inFIGS. 7-9. The alternative embodiment is similar to the embodiment described above with respect toFIGS. 4-6 except that the pathway to the cavity is formed by making one or more holes in theouter layers21,24 rather than removing a strip of the outer layers (e.g., strip42 (FIG. 4)) to form agap50. The various parts of the embodiment ofFIGS. 7-9 correspond with the parts described inFIGS. 4-6.
• FIG. 7 illustrates the preparation of theedge40 of the sandwich panel, e.g.,sandwich panel14, prior to connection with another sandwich panel, e.g.,sandwich panel12, which is prepared in a similar manner.FIGS. 8 and 9 illustrate the alternative embodiment of the angle joint20 formed by connecting thesandwich panels12,14 to one another.
• Referring initially toFIG. 7, theedge40 of thesandwich panel14 is modified by cutting and removing aportion41 of thepanel14. Theedge40 is cut at an angle, e.g., by a miter cut. The miter cut forms anew edge26ato thesandwich panel14. The miter cut also creates anew edge24atoouter layer24 and anew edge25atoouter layer25.
• Rather than removing aportion42 or strip from theouter layer24 to form the pathway to the cavity, one ormore holes52 are formed in theouter layer24. Theholes52 provide the pathway to thecavity44. Theholes52 may be circular in shape and may have a diameter that is several millimeters in length. The diameter of theholes52 may be, for example, about 1 mm-10 mm (millimeters). In one embodiment, the diameter of theholes52 is about 3 mm (millimeters). In the illustrated embodiment, theholes52 are located at or near theedge24aof theouter layer24. It will be appreciated, however, that theholes52 may be formed anywhere in theouter layer24 and may not be circular in shape. It also will be appreciated that a number of holes may be formed in theouter layer24 to provide multiple pathways to thecavity44. For instance, two ormore holes52 may be evenly spaced (or unevenly spaced or staggered) along the length of theouter layer24. It also will be appreciated that thecore26,outer layers24,25 and holes52 may be formed or molded in the configuration ofFIG. 7, e.g. by a mold or by forming the holes during the manufacturing process.
• As shown inFIGS. 8 and 9,sandwich panel12 is prepared or shaped in a similar manner tosandwich panel14, with ahole52 or multiple holes, which provide a pathway to the cavity of thesandwich panel14. The respective cavities (e.g., cavity44 (FIG. 7)) of thepanels12,14 also are aligned with one another to form a combined cavity47 (also referred to as a “cavity”). Theholes52 may be aligned with one another to form one or more pathways to the combinedcavity47. Although theholes52 are shown as being located at or near theouter corner33, it will be appreciated that theholes52 may be located anywhere in theouter layers21,24. It also will be appreciated that theholes52 may be formed in only one of the outer layers (e.g., outer layer24) and not in the other outer layer (e.g., outer layer21).
• Bonding material35 is injected through theholes52 in theouter layers21,24 and into thecavity47. Thebonding material35 fills thecavity47 and spans across theedge30bof theinterface30 to seal theentranceways30a,30bto theinterface30. Thebonding material35 also securely connects thesandwich panels12,14 to one another.
• In the embodiments ofFIGS. 6 and 9, thepanels12,14 are arranged such that there is no gap between thepanel cores23,26 at theinterface30 of the joint20. As will be appreciated, a thermal insulating property of foam material is achieved due to the numerous dead air spaces in the foam material. It is desirable to avoid collapsing walls forming such dead air spaces to maintain such thermal insulation property. In the illustrated embodiments of the invention theedges23a,26aof the adjacent cores abut each other in a manner such that a substantially continuous dead air space and thermal insulating effect is achieved on both sides of the joint20 where theedges23a,26aabut. Moreover, as the foam material of which the cores are made may have some capability of being compressed when pressed, e.g., by a compressive force as theedges23a,26aare urged into engagement with each other, there may be some extent of compression of the foam material of the respective cores at the abutting surfaces thereof, and, in a sense, this affords a forgiveness to allow for intimate engagement of the two abutting cores even if theedges23a,26aare not perfectly straight. Such intimate engaging of theedges23a,26ahelp to assure maintaining of continuity of thermal insulating property of a wall that is made of adjacent sandwich panels.
• Referring back toFIG. 3, thecore26 of the sandwich panel, e.g., thesandwich panel14, may be formed from a light-weight, insulative material, for example, polyurethane, expanded polystyrene, polystyrene hard foam, Styrofoam® material, phenol foam, a natural foam, for example, foams made from cellulose materials, such as a cellulosic corn-based foam, or a combination of several different materials. Other exemplary core materials include honeycomb that can be made of polypropylene, non-flammable impregnated paper or other composite materials. It will be appreciated that these materials insulate the interior of the structure and also reduce the sound or noise transmitted through the panels, e.g., from one outer surface to the other or from an exterior10eto an interior10iof the building, etc. The core may be any desired thickness and may be, for example, 20 mm (millimeters)-100 mm (millimeters) thick, however, it will be appreciated that the core can be thinner than 20 mm (millimeters) or thicker than 100 mm (millimeters) as may be desired. In one embodiment, the core is about 40 mm (millimeters) thick.
• Theouter layers24,25 of a sandwich panel, e.g.,sandwich panel14, are made from a composite material that includes a matrix material and a filler or reinforcement material. Exemplary matrix materials include a resin or mixture of resins, e.g., epoxy resin, polyester resin, vinyl ester resin, natural (or non oil-based) resin or phenolic resin, etc. Exemplary filler or reinforcement materials include fiberglass, glass fabric, carbon fiber, or aramid fiber, etc. Other filler or reinforcement materials include, for example, one or more natural fibers, such as, jute, cocoa, hemp, or elephant grass, balsa wood, or bamboo.
• Theouter layers24,25 (also referred to as laminate) may be relatively thin with respect to thepanel core26. Theouter layers24,25 may be several millimeters thick and may be, for example, between about 1 mm-12 mm (millimeters) thick, however, it will be appreciated that the outer layers can be thinner than 1 mm (millimeter) or thicker than 12 mm (millimeters) as may be desired. In one embodiment, the outer layers are about 1-3 mm (millimeters) thick.
• It will be appreciated that theouter layers24,25 may be made thicker by layering several layers of reinforcement material on top of one another. The thickness of the reinforcement material also may be varied to obtain thickerouter layers24,25 with a single layer of reinforcement material. Further, different reinforcement materials may be thicker than others and may be selected based upon the desired thickness of the outer layers.
• Theouter layers24,25 are adhered to the core26 with the matrix materials, such as a resin mixture. Once cured, theouter layers24,25 of thesandwich panel14 are firmly adhered to both sides of thepanel core26, forming a rigid building element. It will be appreciated that the resin mixture also may include additional agents, such as, for example, flame retardants, mold suppressants, curing agents, hardeners, etc. Coatings may be applied to theouter layers24,25, such as, for example, finish coats, paint, etc.
• The core26 may provide good thermal insulation properties and structural properties. Theouter layers24,25 may add to those properties of the core and also may protect the core26 from damage. Theouter layers24,25 also provide rigidity and support to the sandwich panel.
• The sandwich panels may be any shape. In one embodiment, the sandwich panels are rectangular in shape and may be several meters, or more, in height and width. The sandwich panels also may be other shapes and sizes. The combination of thecore26 andouter layers24,25 create sandwich panels with high ultimate strength, which is the maximum stress the panels can withstand, and high tensile strength, which is the maximum amount of tensile stress that the panels can withstand before failure. The compressive strength of the panels is such that the panels may be used as both load bearing and non-load bearing walls. In one embodiment, the panels have a load capacity of at least 50 tons per square meter in the vertical direction (indicated by arrows V inFIG. 3) and 2 tons per square meter in the horizontal direction (indicated by arrows H inFIG. 3). The sandwich panels may have other strength characteristics as will be appreciated in the art.
• Internal stiffeners may be integrated into thepanel core26 to increase the overall stiffness of thesandwich panel14. In one embodiment, the stiffeners are made from materials having the same thermal expansion properties as the materials used to construct the panel, such that the stiffeners expand and contract with the rest of the panel when the panel is heated or cooled.
• The stiffeners may be made from the same material used to construct the outer layers of the panel. The stiffeners may be made from composite materials and may be placed perpendicular to the top and bottom of the panels and spaced, for example, at distances of 15 cm (centimeters), 25 cm, 50 cm, or 100 cm. Alternatively, the stiffeners may be placed at different angles, such as a 45-degree angle with respect to the top and bottom of the panel, or at another angle, as may be desired.
• The bonding material used to connect the panels together has the same general thermal expansion characteristics as the materials used to construct the sandwich panel. In one embodiment, the glue is more flexible or bendable than the sandwich panels, and may be, for example, four or five times more flexible than the panels. The flexibility of the glue, therefore, reduces the likelihood than the joints of the monolithic structure will break or split, and also transmits loads from one panel to another, across the joint. The bonding material may include filling components, such as, fiberglass or a fiberglass and resin mixture, and may be, for example, microfiber and Aerosil®.
• As is described herein the angle joint, e.g. angle joint20, generally does not create a thermal bridge from one side of the panel to the other side of the panel. The joint is formed by the cores of adjacent panels, which are in contact with one another. The glue or bonding material in the cavity and at the inner corner holds or secures the panels to one another and also seals the entranceways to theinterface30 between thepanel cores23,26. The resulting joint minimizes, reduces or eliminates thermal transmissions from one side of the panel to the other side of the panel.
• Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings.

Claims (28)

1. An angle joint between a first sandwich panel and a second sandwich panel, the angle joint comprising:

a first sandwich panel having a first outer layer and a second outer layer spaced from the first outer layer by a panel core, and an angle edge comprised of an edge portion of the panel core and an edge portion of the first outer layer;

a second sandwich panel having a first outer layer and a second outer layer spaced from the first outer layer by a panel core, and an angle edge comprised of an edge portion of the panel core and an edge portion of the first outer layer, wherein the angle edges of the sandwich panels are in contact with one another at an interface between the panel cores, an entranceway to the interface between the panel cores at an inner corner comprised of the edge portions of the first outer layers;

a cavity in the panel cores, the cavity defined by a portion of the second outer layers and a portion of each panel core, the cavity spanning across a second entranceway to the interface between panel cores; and

bonding material in the cavity and at the inner corner to connect the first sandwich panel to the second sandwich panel.

2. The joint ofclaim 1, further comprising a pathway through at least one of the second outer layers to the cavity and through which the bonding material is injectable.

3. The joint ofclaim 2, wherein the pathway is a gap between an edge of the second outer layer of the first sandwich panel and an edge of the second outer layer of the second sandwich panel.

4. The joint ofclaim 3, further comprising an outer corner comprised of bonding material between the edges of the second outer layers.

5. The joint ofclaim 2, wherein the pathway is a hole formed in the second outer layer of at least one of the sandwich panels.

6. The joint ofclaim 5, wherein the angle edge of each sandwich panel further comprises an edge portion of the second outer layer of the sandwich panel, and the joint further comprises an outer corner comprised of the edge portions of the second outer layer of each sandwich panel.

7. The joint ofclaim 1, wherein the cavity extends along a length of the second outer layer of each sandwich panel, wherein the length of the cavity along the second outer layer is at least seven times greater than a thickness of the second outer layer.

8. The joint ofclaim 7, wherein the cavity extends perpendicularly from the second outer layer of each sandwich panel along a length of the panel core, wherein the length of the cavity extending perpendicularly into the panel core is at least seven times greater than the thickness of the second outer layer.

9. The joint ofclaim 1, wherein the bonding material in the cavity and at the inner corner seals entranceway to the interface between the panel cores, and the interface is dead air space.

10. The joint ofclaim 9, wherein the interface between the sandwich panel cores inhibits thermal transmissions across the joint from the first outer layer to the second outer layer.

11. The joint ofclaim 1, wherein the bonding material at the inner corner has a radius.

12. The joint ofclaim 1, wherein the panel cores are comprised of insulating materials and the first and second outer layers are comprised of composite materials.

13. A method of joining two sandwich panels in a non-linear orientation, the sandwich panels having a core, an outer layer covering at least one surface of the core, an angle edge and a cavity, the method comprising:

placing the panels edge to edge to form an interface in an area between the panel cores and a combined cavity; and

applying bonding material in the cavity to hold the panels together and to block thermal transmissions across the joint.

14. The method ofclaim 13, wherein the applying step further comprises injecting bonding material into the cavity through a gap in the edges of the outer layers of the sandwich panels.

15. The method ofclaim 13, wherein the applying step further comprises injecting bonding material into the cavity through at least one hole in at least one of the outer layers.

16. The method ofclaim 13, wherein the sandwich panels have a second outer layer covering at least one surface of the core, and wherein the placing step further comprises placing the second outer layers edge to edge to form an inner corner of the joint.

17. The method ofclaim 16, further comprising applying bonding material at the inner corner of the joint.

18. A method of joining two sandwich panels with an angle joint, wherein each sandwich panel has a first outer layer and a second outer layer spaced from the first outer layer by a panel core, the method comprising:

removing an edge portion of each panel to form an angle edge, the angle edge comprising a portion of the panel core and an edge of the first outer layer;

placing the angle edges in contact with one another, such that there is an interface between the panel cores and the edges of the first outer layers are in contact with one another to form an inner corner and an entranceway to the interface;

forming a cavity by removing a portion of the panel core, the cavity defined by a portion of the second outer layer of each sandwich panel and a portion of the core;

filling the cavity with a bonding material that spans across a second entranceway to the interface; and

applying bonding material that spans across the entranceway at the inner corner.

19. The method ofclaim 18, wherein the step of forming the cavity comprises removing a portion of the core near the second outer layer of each sandwich panel and a portion of the panel core extending perpendicularly from the second outer layer of each sandwich panel.

20. The method ofclaim 18, wherein step of forming a cavity comprises removing a portion of the panel core near the second outer layer of each sandwich panel that has a length that is at least seven times a thickness of the second outer layer.

21. The method ofclaim 20, wherein step of forming a cavity comprises removing a portion of the panel core extending perpendicularly from the second outer layer of each sandwich panel that has a length that is at least seven times the thickness of the second outer layer.

22. The method ofclaim 18, further comprising the step of forming a pathway to the cavity by removing a portion of the second outer layer of at least one of the sandwich panels.

23. The method ofclaim 22, comprising removing a portion from the second outer layer of at least one of the sandwich panels to form a hole.

24. The method ofclaim 22, wherein the step of forming a pathway comprises removing a strip of the second outer layer from each of the sandwich panels to form an edge of the second outer layer of each sandwich panel, wherein the edges of the second layers are spaced from one another to form a gap.

25. The method ofclaim 22, further comprising spreading bonding material between the edges of the second outer layers to form an outer corner.

26. The method ofclaim 18, further comprising installing the sandwich panels are as part of a monolithic building.

27. A sandwich panel comprised of:

a first outer layer and a second outer layer, the outer layers separated from one another by an insulative core;

an angle edge comprised of a portion of the insulative core and a portion of the first outer layer;

a cavity in the insulative core, the cavity defined by a portion of the second outer layer and a portion of the core; and

a pathway through the second outer layer to the cavity through which a bonding material may be injected to form an angle joint between the sandwich panel and an adjacent construction element, wherein the insulative core inhibits thermal transfer across the joint from the first outer layer to the second outer layer.

28. A method of forming a sandwich panel comprising:

mounting a first outer layer to a core;

mounting a second outer layer to the core;

forming an angle edge of the sandwich panel, the angle edge comprising a portion of the first outer layer and a portion of the core;

forming a cavity between a portion of the second outer layer and a portion of the core; and

providing access to the cavity through the second outer layer with a pathway through which bonding material is injectable to form a joint between the angle edge of the sandwich panel and a construction element in a manner that inhibits thermal transmissions across the joint.

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