US20100132279A1 - Skylight with multi-layer polymeric panel - Google Patents

Abstract

A skylight is formed with a pair of plastic panels having outer peripheral flanges and a central region transparent to visible light, aligned in a stacked orientation with the peripheral flanges overlying one another and defining an enclosed central region in-between. An inner and outer pair of circumferentially oriented spacer frames are interposed between and bonded to the outer peripheral flanges of elastic panels to form a sealed enclosed region. A peripheral frame is formed in situ about the plastic panels from a moldable polymeric material which entraps the peripheral flanges forming an integral leakproof structure with the spacer frames preventing intrusion of the moldable polymeric frame material into the enclosed region.

Description

BACKGROUND OF THE INVENTION
• 1. Field of the Invention
• The present invention relates to a window containing structures having a molded polymeric frame extending about the outer peripheral flange of a pair of spaced apart light transparent plastic panels.
• 2. Background Art
• Window containing structures in buildings such as a skylights, window assemblies and certain types of doors, are typically formed of a light transparent panel of glass or plastic mounted in a peripheral frame formed of wood, metal or extruded plastic. In order to provide good thermal insulation, two spaced apart transparent layers are frequently utilized creating an enclosed region there between which is filled with gas. Windows and doors typically use a pair of glass transparent panels joined together about their outer peripheral edge by a spacer forming an insulated glass unit (IGU). Skylights can alternatively be formed with glass panels or plastic panels. Since skylights typically do not require the same degree of optical quality as windows, low cost and light weight plastic panels can be utilized in place of glass. In order to achieve structural rigidity, the plastic panels are frequently, outwardly, domed in a convex manner, the peripheral edges of the plastic panels mounted in a rectangular or circular mounted frame. Typically, the periphery of the plastic panels are attached to the frame interposed between a frame curb portion and a mounting flange and held together by a series of fasteners.
• In U.S. patent publication application No. 2005-0178078-A1 published Aug. 18, 2005, which is incorporated by reference in its entirety, a window containing assembly with a molded plastic frame is disclosed. Several embodiments provide a peripheral polymeric frame molded about a multi-layer light transparent panel of glass or plastic. A spacer/seal joins the panels and prevents plastic from intruding into the internal central region of the panel assembly during molding.
SUMMARY OF THE INVENTION
• It is an object of the present invention to manufacture windows having a molded plastic frame and a multi-layer plastic skylight panel. It is therefore important to prevent intrusion of the moldable plastic frame material into the central region of the overlapping plastic panels. It is necessary to have a good seal when the mold is closed between the spacer and the peripheral plastic panels. When plastic panels are vacuum formed or sag bent into a dome shape, it is common to have some variations in the peripheral flange flatness, particularly in the corner regions. These variations in flatness between adjacent plastic panels can result in a leak path enabling polymeric material to intrude into the central region of the light transmission layer pair which can adversely affect frame strength as well as providing an unsightly protrusion into the visible area of the window.
• It is an object of the present invention to provide a skylight having a good seal between the outer peripheral flanges of the plastic light transparent panels to prevent intrusion of the moldable plastic material of the frame during the molding process into the enclosed region of the plastic panels, while accommodating normally occurring flatness variations between panels resulting from plastic panel thermoforming.
• It is a further desired to significantly space apart the edges of the plastic panels to achieve an assembled finished edge thickness approximate that of a glass IGU so that both glass and plastic glazing panel skylights can be made in the same mold.
• Accordingly a glazing unit is provided having a pair of plastic light transparent panels aligned in stacked relation having cooperating outer peripheral flanges which overlie one another. The outer peripheral flanges are bonded together utilizing a tubular metal spacer positioned there between and bonded to the plastic panels. A peripheral frame is then formed in situ of a molded polymeric material about the pair of plastic panels entrapping the peripheral flanges forming a leak tight structure.
• The glazing unit of the present invention is particularly well suited for use as a skylight in both small residential and large commercial applications. The tubular metal spacer is bonded to the pair of plastic panels to align the panels, seal their outer periphery and to make the assembly easy to handle when inserting into a mold. The mold is then closed and a moldable polymeric material is introduced into the mold cavity forming a unitary peripheral flange in situ about the peripheral edge of the plastic panels.
• In one of the embodiments of the invention illustrated, the pair of plastic light transmitting panels are formed of acrylic. The tubular spacer is made of thin wall aluminum segments joined by corner keys into the shape of a rectangle and bonded to the spaced apart panel flanges. Once joined, the stacked sub-assembly is inserted into a mold for forming a frame thereabout. The mold is then closed and moldable polymeric material is injected into the mold cavity forming a frame in situ which is securely bonded to the peripheral flanges of the plastic panels forming a leak tight joint between the peripheral frame and the entrapped peripheral flanges of the transparent plastic panels. The assembly is then removed from the mold.
• In one embodiment of the invention, the method is practiced by injecting a RIM polymeric material into the mold and in another, a thermoplastic material is used.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a skylight assembly installed in a building;
• FIG. 2 is a perspective view of a first skylight embodiment of the invention;
• FIG. 3 is a cross-section taken along section3-3 ofFIG. 2;
• FIG. 4 is a cross-section of an alternative embodiment;
• FIG. 5 is a top plan exploded partial view of a spacer corner joint;
• FIG. 6 is an exploded cross-sectional side view illustrating the placement of the spacers relative to the edges of the plastic panels;
• FIG. 7 is a top plan view illustrating a joint formed in the two-sided elastic tape strip; and
• FIG. 8 is a cross-sectional view of an alternative twin spacer frame member.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
• As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to utilize the present invention.
• FIG. 1 illustrates abuilding10 having asloped roof12 on which askylight assembly14 is mounted. Theskylight assembly14 has a centralinsulating glazing unit16 made up of two or more pairs of plastic panels which are at least semi-transparent to visible light. Skylight14 is further provided with aperipheral frame18 which is molded about the periphery of theinsulating glazing unit16.Frame18 is affixed to thebuilding roof12 in a weather-tight manner.Frame18 can be mounted to a conventional skylight roof curb or as illustrated inFIGS. 2 and 3,frame18 can be integrally formed with acurb20 and a flashingmember22. Insulatingglazing unit16 is made up of a pair of plastic panels,inner panel24 andouter panel26, each formed in the shape of a dome and spaced apart to define a central enclosedregion28 therebetween. Enclosedregion28 can be form filled with air or other gases, such as Argon.
• Theinsulating glazing unit16 has acenter section30 which is at least semi-transparent to visible light and a surroundingperipheral flange32 which is affixed toframe18. The pair ofplastic panels24 and26 each have a transparent central section and a corresponding peripheral flange. The peripheral flanges of the inner and outer plastic panels are joined together by a pair of spaced apartcircumferential spacer frames34 and36. Each of the spacer frames forms a continuous loop extending circumferentially about and inboard of the outer peripheral-most edge of the pair ofplastic panels24 and26. The outer peripheral edge of the plastic panel generally lies along acommon plane38, shown inFIG. 3, which is generally perpendicular tocenterline40 illustrated inFIGS. 2 and 3.Inner spacer frame34 is located closer tocenterline40 thanouter spacer frame36 as illustrated in cross-sectional view.Spacer frames34 and36 are transversely spaced apart. Theinner spacer frame34 is oriented slightly outboard of the junction between the innermost edge offrame18 and theplastic panels24 and26.Outer spacer frame36 is located approximate and preferably slightly inboard of the outermost peripheral edge of theplastic panels24 and26.
• In the embodiment illustrated inFIG. 3, the inner and outer spacer frames34 and36 are preferably a tubular aluminum spacer channel of the type commonly used to form glass dual pane insulated glazing units. The specific aluminum rectangular spacer used has a height of 0.50 inches and a width of 3.15 inches with a 0.10 inch wall thickness. The top and bottom of the planar surfaces of thespacers34 and36 are coated with a polyurethane caulk-like adhesive and the inner and outer spacers are placed on one of theplastic panels24 or26. The other plastic panel is then installed in an aligned stacked orientation securely bonding the panels together. The inner and outer spacer frames34 and36 are each generally rectangular in shape in plan view and are made up of four linear segments oftubular frame segments42 interconnected at the corners bycorner keys44.Corner keys44 are plastic L-shaped members having flexible projections which are inserted inside of thetubular frame segments42. An exploded cross-sectional view showing the overlying peripheral flange of inner and outerplastic panel24 and26 and inner and outer spacer frames34 and36 is illustrated inFIG. 6. As previously indicated, the top and bottom surfaces of each of the inner and outerspacer frame members34,36 is coated with an adhesive which is compatible with the plastic material ofpanels24 and26, as well as being compatible with the material offrame18. A top plan view of a corner section of the assembled inner and outer plastic panel assembly is shown inFIG. 7.
• The panel assembly which forms an insulating glazing unit is inserted into a mold andframe18 is molded thereabout in situ securely entrapping theperipheral flange32 of the insulatingglazing unit16. Theframe18 forms a securely tight seal with the insulating glazing unit in a manner similar to that described in U.S. Patent Publication No. 2005-0178078, previously incorporated by reference. A preferred material for formingperipheral frame18 is a polyurethane RIM material. However, other materials, including thermoplastics, could be utilized in practicing the invention. The structure of the present inner and outer spacer frames addresses two problems. One is the necessity to provide a secure leak-tight joint between the plastic panel peripheral flanges to prevent intrusion of polymetric material used to mold theperipheral frame18. The second is the inner and outer space frame construction further enables very substantial peripheral flange thicknesses to be achieved with an insulating and glazing unit having a plastic inner and outer panel. A thick peripheral flange enables one skylight mold to be used to produce both glass skylights, as well as domed plastic skylights. The height of the inner and outer spacer frames is selected so that when inserted between the peripheral flanges of the outer andinner panels24,26 with the appropriate adhesive layers therebetween, the overall stack height of the peripheral frame approximates that of a glass thermal pane insulating glazing unit when clamped in the mold prior to plastic injection.
• Inner space frame34 provides the necessary structural rigidity when the mold is clamped closed. Theouter spacer frame36 serves to securely bond the peripheral flanges of the outer and inner plastic panels together in a leak-tight manner and provide the necessary resistance to the inward forces from the injected polymeric material used to formperipheral frame18. As previously described, each of the inner and outer spacer frames are formed of a series ofstraight frame segments42 interconnected bycorner keys44. Preferably, the frame segments have a width between 0.2 and 0.5 inches and a height of 0.4 to 0.8 inches. Preferably, the inner and outer spacer frames will be spaced transversely apart 0.20 to 1.5 inches, as dictated by the selected peripheral flange size. Preferably, the outer spacer frame is inwardly inset relative to the outermost edge of the peripheral flange by 0.1 to 0.25 inches.
• The preferred spacer frame illustrated inFIGS. 3-6 is an aluminum rectangle which is roll-formed and mechanically joined into a closed tube. Alternative spacer frames can be used, such as commercially available stainless steel roll-form spacers, as well as commercially available metal/silicon foam composite spacer frames used in Argon gas filled insulating glass units.
• In the preferred embodiment, the skylight plastic outer andinner panels24 and26 are formed of acrylic. If desired, the inner or outer plastic panels may be coated with an optical or thermal layer in order to regulate light transmittance in the heat transfer. As an alternative to acrylic, other materials can be used, such as polycarbon or a PET. Due to the exposure to indirect sunlight, it may be necessary to apply a UV barrier when UV sensitive plastic panels are utilized. When fabricating very large skylights, it may be advantageous to include reinforcing fibers, such as chopped glass in with the moldable polymetric material utilized to form theframe18.
• As mentioned previously,frame18 may be integrally formed with acurb20 and a flashing22, as illustrated inFIGS. 2 and 3. Alternatively, askylight assembly50, illustrated inFIG. 4, may be provided with aframe52 for mounting directly upon a pre-existing curb (not shown). Whenframe52 is designed for a curb mount, a downwardly extending mountingflange54 may be provided onframe52 for affixing the frame to the curb. Conventional fasteners can be installed through a series of mountingholes56 provided in the mountingflange54.
• As an alternative to using separate inner and outer spacer frames34 and36, as previously described, the inner and outer spacer frames can be formed together by making a generally figure eight shape rollform frame spacer60 illustrated inFIG. 8. The ends of elongate frame segments of thespacer60 will be stair-step cut so thatconventional corner keys44 can be utilized. Alternatively, a custom corner key can be fabricated enabling the frame segments to be cut either square or mitered. The figure eight shapedframe spacer60 illustrated inFIG. 8 controls the spacing between the inner and outer frame segments thereby easing the assembly process. The top and bottom surfaces of thespacer60 are provided with the series ofshallow grooves62 as illustrated to receive a bead of construction adhesive used to assemble the spacer frame between the spaced-apart inner and outer plastic panel flanges. Of course, a wide variety spacer frame cross-sectional designs could be utilized when practicing the present invention.
• While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.

Claims (19)

1. A skylight assembly comprising:

a pair of plastic panels each having a generally similarly sized outer peripheral flange and a central region which is at least semi-transparent to visible light, the pair of plastic panels when aligned in stacked relation with the outer peripheral flanges generally overlying the inner periphery flanges;

an inner and outer pair of circumferentially oriented spacer frames interposed between and bonded to the outer peripheral flanges of the pair of plastic panels to form a central enclosed region which is filled with gas and bounded by the inner spacer frame and a central section of the pair of plastic panels; and

a peripheral frame formed in situ of a moldable polymeric material bonded to the outer spacer frame and the peripheral flanges of the pair of plastic panels, entrapping the peripheral flanges and forming a leak tight structural joint therewith;

wherein the outer spacer frame provides a seal between the peripheral flanges of the pair of plastic panels as the peripheral frame is molded preventing intrusion of the moldable polymeric material into the central enclosed region.

2. The skylight assembly ofclaim 1 wherein the inner and outer pair of circumferentially oriented spacer frames each have an upper and lower surface coated with adhesive.

3. The skylight assembly ofclaim 1 wherein the inner and outer pair of circumferentially oriented spacer frames each have a width of 0.20 to 0.50 inches.

4. The skylight assembly ofclaim 1 wherein the inner and outer pair of circumferentially oriented spacer frames each comprises a segment having a hollow generally rectangle cross-section.

5. The skylight assembly ofclaim 4 wherein the inner and outer pair of circumferentially oriented spacer frames are spaced apart 0.2 to 1.00 inches.

6. The skylight assembly ofclaim 4 wherein the inner and outer pair of circumferentially oriented spacer frames comprise a plurality of linear segments interconnected by corner keys to form a pair of continuous frames.

7. The skylight assembly ofclaim 6 wherein the linear segments forming the inner and outer pair of circumferentially oriented spacer frames each have a width of 0.20 to 0.50 inches and a height of 0.40 to 0.80 inches.

8. The skylight assembly ofclaim 1 wherein the outer spacer frame is inwardly inset from the outer most edge of the peripheral flange by 0.10 to 0.25 inches.

9. The skylight assembly ofclaim 1 wherein the plastic panels are formed of acrylic.

10. The skylight assembly ofclaim 1 wherein the plastic panels are formed of poly carbonate.

11. The skylight assembly ofclaim 1 wherein the peripheral frame is formed of a RIM material.

12. The skylight assembly ofclaim 1 wherein the peripheral frame is formed of a thermoplastic material.

13. The skylight assembly ofclaim 1 wherein the thermoplastic material is filled with reinforcing fibers.

14. The skylight assembly ofclaim 1 wherein the peripheral frame is generally rectangular in shape.

15. The skylight assembly ofclaim 1 wherein the outer peripheral flanges of the pair of plastic panels lie in a plane perpendicular to the central axis.

16. A method of forming a glazing unit comprising:

forming a pair of plastic panels from a sheet of plastic material which is at least semi-transparent to visible light, the pair of plastic panels having an outer peripheral flange and a central region, which, when stacked upon one another, define an enclosed cavity bounded by the spaced apart central regions of the plastic panels when overlying one another;

bonding an inner and outer pair of circumferentially oriented spacer frames between the outer peripheral flanges of the pair of plastic panels to form a central enclosed region which is filled with gas bounded by the inner spacer frame and the pair of plastic panels;

inserting the bonded pair of plastic panels into a skylight frame mold so that the mold entraps the peripheral flanges of the stacked pair of plastic panels;

injecting a moldable polymeric material into the mold forming a frame which is securely bonded to the peripheral flanges of the plastic panels and the outer spacer frame wherein the outer spacer frame prevents the a moldable polymeric material from entering into the central region formed between the plastic panels; and

removing the skylight assembly from the mold.

17. The method ofclaim 16 wherein the moldable polymeric material comprises RIM.

18. The method ofclaim 16 wherein the moldable polymeric material comprises a thermoplastic.

19. The method ofclaim 16 wherein the pair of plastic panels are formed of acrylic.

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