WO2009125289A2

WO2009125289A2 - Straight joint for sandwich panels and method of fabricating same

Info

Publication number: WO2009125289A2
Application number: PCT/IB2009/005223
Authority: WO
Inventors: Ulrich Schwartau
Original assignee: Innovida Factories, Ltd.
Priority date: 2008-04-11
Filing date: 2009-04-13
Publication date: 2009-10-15
Also published as: US20090255204A1; WO2009125289A3

Abstract

A straight joint and method for connecting two adjacent construction elements such as sandwich panels, so as to reduce or minimize thermal bridging across the elements. The sandwich panels each have a core (33, 33'), an outer layer (32, 32'), a cavity (37) defined by a portion of the core, and a pathway (32c 32c') through the outer layer to the cavity. The panels are erected such that the panel cores are in contact with one another. Bonding material (40) is injected into the cavity through the pathway to seal the joint and maintain the panels in fixed relation to one another.

Description

STRAIGHT JOINT FOR SANDWICH PANELS AND METHOD OF FABRICATING SAME

RELATED APPLICATION DATA

This application is a claims priority to U.S. Patent Application No. 12/101,620 filed April 11, 2008, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to constructing buildings, and more particularly, to connecting adjacent sandwich panels with a straight joint without creating a thermal bridge across the joint.

DESCRIPTION OF THE RELATED ART

There is an increasing 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, tornados, 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 also reduce or lower the ownership costs.

SUMMARY

The present invention provides an alternative to conventional construction materials and techniques. Structures, for example, buildings, houses, commercial buildings, warehouses, recreational vehicle (RV) trailers, mobile homes, manufactured homes, and modular homes, etc., can be constructed by composite sandwich panels, which have an insulative core and one or more outer layers. The structures can be constructed by connecting several sandwich panels together with a bonding material, and usually 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. The composite 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. Because they weigh less than traditional building materials, the handling and transport of composite sandwich panels is generally less expensive. The composite sandwich panels also can be used to produce lightweight structures, such as floating houses, mobile homes, or travel trailers, etc.

Sandwich panels are generally more elastic or flexible than conventional materials such as 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 nonflammable, waterproof and very strong and durable, and in some cases able to resist hurricane-force winds (up to 300Kph (kilometers per hour)). The panels also may be resistant to the detrimental effects of algae, fungicides, water, and osmosis. As a result, buildings constructed from sandwich panels are better able to withstanding earthquakes, floods, tornados, hurricanes, fires and other natural disasters than buildings constructed from conventional materials.

To build a wall, two or more adjacent construction elements, e.g., sandwich panels, can be connected together by a straight joint. It is generally desirable to avoid creating a thermal bridge across the joint from one side of wall 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.

In order to connect sandwich panels without creating a thermal bridge across the joint between the panels, a cavity is formed in each panel. A pathway to the cavity is created, for example, by making a hole through the outer layer or by removing a strip of the outer layer near the edge of the panel to provide a gap between the outer layers of the panels being connected. Adjacent sandwich panels are erected and installed by aligning the panel cores to one another, such that the core of one panel is in physical contact with the core of the adjacent panel. Bonding material is injected through the pathway and into the cavity.

The pathway between the panel cores is closed by the bonding material, which also holds or secures the panels to one another to form a rigid, monolithic wall. The resulting straight 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, a straight joint to connect two adjacent construction elements together, the joint including two panels, each having a core, an outer layer, and a cavity defined by a portion of the core and a portion of the outer layer, the panels arranged such that the panel cores abut one another, a pathway through the outer layer of at least one of the panels to the cavity, and a bonding material injectable through the pathway and into the cavity, the bonding material bonding the panels together.

According to one embodiment of the straight joint, the core of each panel includes an edge, and the edges of each panel core are in contact with one another. According to another embodiment of the straight joint, the cavity extends along a length of the outer layer of each panel, wherein the length of the cavity along the outer layer is at least seven times greater than a thickness of the outer layer.

According to another embodiment of the straight joint, the cavity extends perpendicularly from the outer layer along a length of the core, wherein the length of the cavity extending perpendicularly into the core is at least seven times greater than the thickness of the outer layer.

According to another embodiment of the straight joint, the pathway is a gap between the edges of the adjacent panels.

According to another embodiment of the straight joint, the gap is defined by an edge of the outer layers of each panel.

According to another embodiment of the straight joint, the pathway includes at least one hole.

According to another embodiment of the straight joint, each panel further includes a second outer layer spaced from the first outer layer by the panel core, a second cavity defined by a portion of the core and a portion of the second outer layer, a second pathway through the second outer layer of at least one of the panels to the second cavity, and bonding material in the second cavity.

According to another embodiment of the straight joint, the second cavity is thermally separated from the first cavity by the abutment of the panel cores.

According to another embodiment of the straight joint, the panel cores inhibit thermal transmissions across the joint.

According to another embodiment of the straight joint, the panel cores are insulating materials.

According to another embodiment of the straight joint, the outer layer is comprised of composite materials.

According to another aspect of the present invention, a method of joining sandwich panels with a straight joint, wherein each panel has a core and an outer layer, the method includes forming a cavity between a portion of the outer layer and a portion of the core of each panel, arranging the panels such that the panel cores abut one another at an edge of each core and the cavities of the respective sandwich panels align to form a combined cavity, providing a pathway to the combined cavity through the outer layer of at least one of the panels, and filling the combined cavity with an bonding material.

According to another embodiment of the method, the cavities are formed by removing a portion of the core near the outer layer and a portion of the core extending perpendicularly from the outer layer.

According to another embodiment of the method, the portion of the core removed near the outer layer has a length that is at least seven times a thickness of the outer layer.

According to another embodiment of the method, the portion of the core extending perpendicularly from the outer layer has a length that is at least seven times the thickness of the outer layer.

According to another embodiment of the method, the cavity is triangular.

According to another embodiment of the method, the step of providing a pathway includes removing a portion of the outer layer of at least one of the panels. According to another embodiment of the method, the portion removed forms a hole in the outer layer.

According to another embodiment of the method, the portion removed is a strip of the outer layer near the edge of the panel core such that a gap is formed between the edges outer layers of each panel.

According to another embodiment of the method, the panels are installed as part of a building.

According to another embodiment of the method, the building is a monolithic structure.

According to another embodiment of the method, the straight joint is resistant to thermal transmissions from one side of the panels to the other side of the panels.

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, a cavity formed in the insulative core, the cavity defined by a portion of the first outer layer and a portion of the core, and a pathway through the first outer layer to the cavity through which a bonding material may be injected to form a 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 includes mounting an outer layer to a core, forming a cavity between a portion of the outer layer and a portion of the core, and providing access to the cavity through the outer layer with a pathway through which bonding material is injectable to join the sandwich panel to a construction element.

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 a straight joint.

FIG. 3 A is an isometric view of a sandwich panel.

FIG. 3B is an isometric view of a sandwich panel with a window and door cutout.

FIG. 4 is an isometric view of a sandwich panel.

FIG. 5A is a fragmentary schematic top sectional view of an edge of a sandwich panel. FIG. 5B is a fragmentary schematic top sectional view of an edge of a sandwich panel prepared for connection to another sandwich panel with a straight joint.

FIG. 6A is a fragmentary schematic top section view of a straight joint between two sandwich panels.

FIG. 6B is a fragmentary schematic top sectional view of a straight joint between two sandwich panels.

FIG. 7A is a fragmentary schematic top sectional view of a straight joint between two sandwich panels.

FIG. 7B is an isometric view of two sandwich panels connected by a straight joint.

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. The components can be oriented in any direction and the terminology should therefore be interpreted to include such variations. 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 building, such as warehouses, commercial buildings, factories, apartments, etc.

The structures described herein are built with composite materials, such as sandwich panels. Sandwich panels, which may be formed from synthetic materials, provide a light-weight and potentially less expensive alternative to conventional raw materials, e.g., wood, concrete, metal, etc. Sandwich panels are usually connected or joined together with a high-strength bonding material, such as epoxy or glue, and conventional materials, such as nails and screws, are not usually needed. The result is a strong and durable monolithic (e.g., single unit) structure, as described further below.

Referring to FIG. 1, an exemplary monolithic structure 10, such as a house, is built from sandwich panels. The house 10 includes of a front wall formed from two sandwich panels 11, 12 connected by a straight joint 13, a side wall formed from two sandwich panels 14, 15 connected by a straight joint 16, and a roof 17. As shown in FIG. 1, the straight joint joins two sandwich panels in a substantially common plane, e.g. a 180-degree joint. Although not shown in FIG. 1, it will be appreciated that the house 10 also includes another side wall and a rear wall, which also may be formed by adjacent sandwich panels connected by straight joints.

As shown in FIG. 1, the walls of the house separate the house into an interior portion 18i and an exterior portion 18e. It generally is desirable to reduce or minimize thermal transmissions from one side of the wall to the other. Therefore, the joints 13, 16 are formed to minimize bridging, or transmission through the joint, from the exterior 18e of the house 10 to the interior 18i of the house 10 or vice versa. The straight joint 16 used to connect the sandwich panels 14, 15 of the side wall is shown in more detail in FIG. 2. Two cavities or voids 20, 21 are formed in the core of the sandwich panels 14, 15 such that one cavity 20 is formed near or may face the exterior 18e of the house 10, and the other cavity 21 is formed near or may face the interior 18i of the house 10. When installed, the cavities 20, 21 are separated from one another by a portion 22 of the panel cores, which are in contact with one another. The panels 14, 15 are then glued together by filling the cavities 20, 21 with a bonding material (shown at 40, 41 in FIG. 6B). The bonding material may be any suitable bonding material such as epoxy, epoxy resin, glue, adhesive, adhering material or another bonding material (these terms may be used interchangeably and equivalently herein). As described in more detail below, the resulting straight joint 16 creates a thermal block across the joint from the exterior 18e to the interior 18i of the structure 10, and thermal transfer between the exterior 18e and interior 18i of the structure 10 is reduced, minimized or eliminated.

As illustrated generally in FIGs. 3A and 3B, the sandwich panel 11 is prefabricated and prepared for installation by cutting the panel to create openings 23, 24 for installing windows, doors, and the like. FIG. 3 A generally illustrates the sandwich panel 11 prior to modification during the prefabrication process. The sandwich panel 11 typically is manufactured in a rectangular shape, but it will be appreciated that the panels may be manufactured in alternative shapes, as may be desired. While a solid rectangular panel is ideal for solid walls (e.g., the side wall comprised of panels 14, 15 in FIG. 1), further processing is necessary if windows 23, doors 24, or other elements are desired. This further processing may be performed at a manufacturing facility or at a construction site.

As shown in FIG. 3B, the sandwich panel 11 may be customized by cutting and removing a portion of the panel 11 to form an opening for a window 23. The window opening 23 may be cut to any desired size to accommodate the installation of any size window. Similarly, a portion of the panel 11 can be cut and removed to form an opening or doorway 24. Also shown in FIG. 3B, a top portion 25 of panel 11 has been removed for installation of an angled eave portion of the roof 17. Although the sandwich panels 11, 12 are shown with window 23 and/or door 24 cutouts, it will be appreciated that the panel can be customized in any manner desired to meet the specifications of an architectural or design plan. For example, as shown in FIG. 1, the panel 12 includes several window openings 23 and no door opening, while panels 14, 15 are solid walls. The sandwich panels also may be cut in other designs to accommodate other roof, wall, etc. arrangements. It also will be appreciated that while the windows, door and roof are described as being cut from a solid sandwich panel, the openings may be molded or otherwise formed in the panel.

An exemplary sandwich panel 30 is shown in FIG. 4. The sandwich panel 30 includes two outer layers 31, 32 separated by a core 33. The core 33 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 exterior 18e to an interior 18i of the building, etc. The core may be any desired thickness and may be, for example, 30 mm (millimeters) - 100 mm (millimeters) thick, however, it will be appreciated that the core can be thinner than 30 mm (millimeters) or thicker than 100 mm (millimeters) as may be desired. In one embodiment, the core is about 60 mm (millimeters) thick.

The outer layers 31, 32 of a sandwich panel, e.g., sandwich panel 30 of FIG. 4, 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, coco, hemp, or elephant grass, balsa wood, or bamboo.

The outer layers 31, 32 (also referred to as laminate) may be relatively thin with respect to the panel core 33. The outer layers 31, 32 may be several millimeters thick and may, for example, be between approximately 1 mm (millimeter) - 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 approximately 1-3 mm (millimeter) thick.

It will be appreciated that the outer layers 31, 32 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 thicker outer layers 31, 32 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.

The outer layers 31, 32 are adhered to the core 33 with the matrix materials, such as the resin mixture. Once cured, the outer layers 31, 32 of the sandwich panel 30 are firmly adhered to both sides of the panel core 33, 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 the outer layers 31, 32, such as, for example, finish coats, paint, etc.

The core 33 may provide good thermal insulation properties and structural properties. The outer layers 31, 32 may add to those properties of the core and also may protect the core 33 from damage. The outer layers 31, 32 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 the core 33 and outer layers 31, 32 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 in FIG. 4) and 2 tons per square meter in the horizontal direction (indicated by arrows H in FIG. 4). The sandwich panels may have other strength characteristics as will be appreciated in the art.

Internal stiffeners may be integrated into the panel core 33 to increase the overall stiffness of the sandwich panel 30. 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.

FIG. 5A depicts a top view of a sandwich panel 30. As shown in FIG. 5A, the edge 33a of the panel is flush or even with the edges 3 Ia, 32a of the outer layers 31, 32. It will be appreciated that while shown in the illustrated embodiment as a generally straight edge, the edge may be shaped, for example into an "S" shape, or another shape. In accordance with one embodiment of the invention, the edges 31a, 32a, 33a of the panel are modified as described below to form a straight joint without a thermal bridge.

Referring now to FIG. 5B, the sandwich panel 30 is prepared by removing a strip of material from the outer layer 31 of the panel, as indicated by the shaded portion 3 Ib, leaving a new edge 31c. Similarly, a strip is removed from the outer layer 32, as indicated by the shaded area 32b, leaving a new edge 32c. The strips may be removed from the panel by cutting the outer layers 31, 32 with a blade or other cutting implement. It will be appreciated that rather than removing a strip of material, one or more holes may be formed in the outer layer to provide access to the cavities 20, 21 (FIG. 1).

After the strips 31b, 32b are removed from the panel, the edge 33a of the core 33 extends slightly beyond the new edges 31c, 32c of the outer layers 31, 32. The portions 31b, 32b that are removed from the outer layers 31, 32 may be several millimeters in length and may be, for example, approximately 2-3 mm (millimeters). As a result, the edge 33a of the core 33 extends approximately 2-3 mm (millimeters) beyond the edges 3 Ic, 32c of the outer layers. It will be appreciated that more or less than 2-3 mm (millimeters) may be removed, as desired.

As shown in FIG. 5B, portions 33b of the core 33 are removed from the panel 30 to create combined cavities 36, 37 (FIG. 6A) when the panels are placed in engagement as described. Bonding material may be placed or injected into the combined cavities 36, 37 to connect the panels together. The portions 33b removed extend along an inner edge of the outer layer 31, 32, designated generally as "A," and also perpendicularly from the outer layer and towards the center of the core 33, designated generally as "B." The dimensions A, B of the portions 33b removed from the core 33 are several millimeters in length, and may, for example be approximately 15-20 mm (millimeters) long.

The dimensions A, B also may be selected based upon the thicknesses of the outer layers 31, 32 according to a desired ratio. The desired ratio of the dimensions A, B to the thickness of the outer layers 31 , 32 may be about seven to one (7:1), or more, e.g., 8: 1 or an even larger ratio. For instance if the outer layers 31, 32 are about 2 mm (millimeters) thick, the dimensions A, B would be at least 14 mm (millimeters), and may be thicker, if desired. The dimensions A, B may be based upon a desired safety factor or based upon the bonding strength of the bonding material.

As shown in FIG. 5B, the portions 33b removed from the core are symmetrical with one another and each form the general shape of an isosceles right triangle, having a 45-degree hypotenuse and legs A, B. It will be appreciated that the cavities formed by removing portions 33b are exemplary of only one embodiment and numerous other configurations may be possible. For example, more core material may be removed for larger (e.g., thicker) outer layers or less core material may be removed for smaller (e.g., thinner) outer layers. Alternatively, the cavity need not be triangular in shape and may, for example, 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 will be appreciated that the core 33 and outer layers 31, 32 may be formed in the configuration of FIG. 5B prior to adhering the outer layers 31, 32 to the core 33, or the sandwich panel may be molded to the desired shape.

The remaining edge 33 a of the core 33 is not removed, and may be left unsealed such that the panel core is exposed. Thus, when several panels are erected and joined by a straight joint, the panel cores may contact one another.

FIGs. 6A and 6B illustrate the process of joining two adjacent panels 30, 30' by a straight joint 16. The panels 30, 30' are erected and fixed adjacent to one another in the desired positions, for example, as the side wall of the house 10. The panels 30, 30' are placed such that the edges 33a, 33a' are in contact with one another at the straight j oint 16 and there is no gap between the panel cores 33, 33'.

As will be appreciated, 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 fonning such dead air spaces to maintain such thermal insulation property. In the illustrated embodiment of the invention the edges 33a, 33a' of the adjacent cores abut each other in a manner such that a substantially continuous dead air space thermally insulating effect is achieved on both sides of the joint where the edges 33 a, 33 a' abut. 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 the edges 33a, 33a' are 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 the edges 33a, 33a' are not perfectly straight. Such intimate engaging of the edges 33a, 33a' helps to assure maintaining of continuity of thermal insulating property of a wall that is made of adjacent sandwich panels.

While there is no gap between the edges 33a, 33a' of the panel cores, it can be seen in FIG. 6A that there are small gaps between the edges 31c, 31c' and 32c, 32c'. These small gaps provide a pathway to the cavities 36, 37, which are formed by removing the core material, described with respect to FIG. 5B. In one embodiment, approximately 2-3 mm (millimeters) of each outer layer is removed from each panel edge and, therefore, the gaps are approximately 4-6 mm (millimeters) wide. With additional reference to FIG. 6B, bonding material, e.g., glue or another bonding material as described above, is placed, e.g., injected, through the gaps in the outer layers and into the cavities 36, 37 to form the straight joint. Because there is no gap between the panel cores 33a, 33a', the glue fills each of the cavities 36, 37, but does not seep from one cavity to the other. The glue holds the panels 30, 30' rigidly to one another to form the straight joint, such that loads may be transmitted from one panel to the adjacent panel through the glue.

As shown in FIGs. 7A and 7B, and as mentioned above, one or more holes 40 may be formed in the outer layers 31, 31 ', 32, 32' to provide the pathway to the cavities 36, 37. In such a case, the strips 31b, 32b (FIG. 5B) may not be removed from the panel 30 and the edges 31a, 32a of the outer layers 31, 32 of the panel 30 may contact the edges 31a', 32a' of the outer layers 31', 32' of the adjacent sandwich panel 30' when the panels are erected. While the holes are shown along the joint, it will be appreciated that one or more of the holes may be formed in either of the panels. The core 33a of panel 30 may be in contact with, or in close proximity to, the core 33a' of the adjacent panel 30'. Bonding material may be injected through the holes 40 and into the cavities 36, 37 to close the pathway between the panel cores and rigidly connect the panels together, as described above.

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 than the sandwich panels, and may, for example, be 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 be of a resin mixture and include filling components, such as glass fiber and may be, for example, microfiber or Aerosil®.

It will be appreciated that while the straight joint has been described as having two cavities 36, 37 other embodiments are possible, for example, the joint may have a single cavity or, rather than a cavity defined by the outer layer and panel core, a portion of the core may be hollowed and filled with glue, etc.

The straight joint 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 that is inserted into the cavities holds or secures the panels to one another and also seals the entranceway where the panel cores are in contact with one another. The resulting straight 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

CLAIMSWhat is claimed is:

1. A straight j oint to connect two adj acent construction elements together, the j oint comprising: two panels, each having a core, an outer layer, and a cavity defined by a portion of the core and a portion of the outer layer, the panels arranged such that the panel cores abut one another; a pathway through the outer layer of at least one of the panels to the cavity; and a bonding material injectable through the pathway and into the cavity, the bonding material bonding the panels together.

2. The straight joint of claim 1 , wherein the core of each panel includes an edge, and the edges of each panel core are in contact with one another.

3. The straight joint of any one of claims 1-2, wherein the cavity extends along a length of the outer layer of each panel, wherein the length of the cavity along the outer layer is at least seven times greater than a thickness of the outer layer.

4. The straight joint of any one of claims 1-3, wherein the cavity extends perpendicularly from the outer layer along a length of the core, wherein the length of the cavity extending perpendicularly into the core is at least seven times greater than the thickness of the outer layer.

5. The straight joint of any one of claims 1-4, wherein the pathway is a gap between the edges of the adjacent panels

6. The straight joint of claim 5, wherein the gap is defined by an edge of the outer layers of each panel.

7. The straight joint any one of claims 1-6, wherein the pathway includes at least one hole.

8. The straight joint of any one of claims 1-7, wherein each panel further comprises a second outer layer spaced from the first outer layer by the panel core, a second cavity defined by a portion of the core and a portion of the second outer layer, a second pathway through the second outer layer of at least one of the panels to the second cavity, and bonding material in the second cavity.

9. The straight joint of claim 8, wherein the second cavity is thermally separated from the first cavity by the abutment of the panel cores.

10. The straight joint of any one of claims 1-9, wherein the panel cores inhibit thermal transmissions across the joint.

11. The straight joint of any one of claims 1-10, wherein the panel cores are insulating materials.

12. The straight j oint of any one of claims 1-11, wherein the outer layer is comprised of composite materials.

13. A method of joining sandwich panels with a straight joint, wherein each panel has a core and an outer layer, the method comprising: forming a cavity between a portion of the outer layer and a portion of the core of each panel; arranging the panels such that the panel cores abut one another at an edge of each core and the cavities of the respective sandwich panels align to form a combined cavity; providing a pathway to the combined cavity through the outer layer of at least one of the panels; and filling the combined cavity with an bonding material.

14. The method of claim 13, wherein the cavities are formed by removing a portion of the core near the outer layer and a portion of the core extending perpendicularly from the outer layer.

15. The method of claim 14, wherein the portion of the core removed near the outer layer has a length that is at least seven times a thickness of the outer layer.

16. The method of claim 15, wherein the portion of the core extending perpendicularly from the outer layer has a length that is at least seven times the thickness of the outer layer.

17. The method of any one of claims 13-16, wherein the cavity is triangular.

18. The method of any one of claims 13-17, wherein the step of providing a pathway comprises removing a portion of the outer layer of at least one of the panels.

19. The method of claim 18, wherein the portion removed forms a hole in the outer layer.

20. The method of claim 18, wherein the portion removed is a strip of the outer layer near the edge of the panel core such that a gap is formed between the edges outer layers of each panel.

21. The method of any one of claims 13-20, wherein the panels are installed as part of a building.

22. The method of claim 21, wherein the building is a monolithic structure.

23. The method of any one of claims 13-22, wherein the straight j oint is resistant to thermal transmissions from one side of the panels to the other side of the panels.

24. 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; a cavity formed in the insulative core, the cavity defined by a portion of the first outer layer and a portion of the core; and a pathway through the first outer layer to the cavity through which a bonding material may be injected to form a 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.

25. A method of forming a sandwich panel comprising: mounting an outer layer to a core; forming a cavity between a portion of the outer layer and a portion of the core; and providing access to the cavity through the outer layer with a pathway through which bonding material is injectable to join the sandwich panel to a construction element.