Abstract:
A manufacture for reducing thermal transfer through windows has a composite metal/nonmetallic frame and/or a composite vent surround. The metallic and non-metallic components are modular and selectively coupled, such that a range of variations to accommodate different applications may be inter-coupled via common interfaces.

Description:
FIELD 
     The present invention relates to building products and more particularly, to windows and window frames. 
     BACKGROUND 
     Some windows utilize vent surrounds and frames made from metal, e.g., aluminum alloy. Metal windows are in use in residential and commercial buildings, e.g., in storefronts and in curtain walls used on the façade of high-rise buildings. The energy transfer characteristics of windows are an important factor in the overall energy efficiency of a building and there is a continual search for building features and methods of construction that improve energy efficiency. Improved and/or alternative structures and methods for controlling the heat transfer characteristics of windows remain desirable. 
     SUMMARY 
     The disclosed subject matter relates to an access structure for an opening through a building envelope, including a frame structure coupled to the building, framing the opening and a spanning element spanning the frame structure, at least partially covering the opening. The spanning element has at least one panel and a surround embracing the periphery of the panel, the frame structure having a parallel portion extending parallel to the spanning element in a spanning direction and a perpendicular portion extending perpendicular to the spanning element relative to a spanning direction. At least one of the perpendicular portion of the frame structure and the surround being a composite of a metal portion and a non-metal portion, the non-metal portion having a lower thermal conductivity than the metal portion, the non-metal portion being exposed to a first environment on a first side of the building envelope and the metal portion being proximate a second environment on a second side of the building envelope. 
     In one approach, the access structure is a window providing access to light and the at least one panel is a glazing panel. 
     In one approach, the window has an opened and a closed position. 
     In one approach, the surround includes a box portion made from metal and the perpendicular portion includes a non-metallic ledge that attaches to the box portion. 
     In one approach, the box portion has an elongated channel and the non-metallic ledge has an L-shaped cross-sectional shape, the ledge having an insertion leg capable of being received in the elongated channel and forming a portion of the L-shape. 
     In one approach, the ledge has at least one finger extending therefrom in a direction opposite to the insertion leg for reducing airflow proximate the ledge. 
     In one approach, the insertion leg has a plurality of burrs having a directionality that promotes insertion of the insertion leg into the channel and opposes withdrawal therefrom. 
     In one approach, the ledge has a front-to-back slope capable of promoting water runoff. 
     In one approach, the ledge has a plateau at the base of the insertion leg that mates with a mating recess communicating with the channel to establish a given relative orientation. 
     In one approach, the perpendicular portion of the frame has a connection bead that is capable of snap-fitting to an adaptor, the adaptor being non-metallic. 
     In one approach, the adaptor, when in place on the connection bead is proximate at least one seal extending from the surround when the spanning element at least partially covers the opening. 
     In one approach, the connection bead has a bifurcated arrowhead cross-sectional shape having a pair of opposed lead-in surfaces that interact with corresponding sloped surfaces on opposed arms of the adaptor, which define a hollow there between having a shape complementary to the connection bead, the arms resiliently displacing when pushed against the lead-in surfaces and snapping to a closed position when pushed beyond the lead-in surfaces. 
     In one approach, the arrowhead cross-sectional shape has a recess at the tip to receive sealant. 
     In one approach, the window is fixed. 
     In one approach, the access structure is a door. 
     In one approach, the at least one of the composite frame structure and surround are composite via an interlocking interface, such that a plurality of interchangeable parts may be attached at the interface giving rise to modularity supporting use of the access structure for a plurality of different applications. 
     In one approach, both the frame structure and the surround are composite. 
     In one approach, the metal portion is formed from an aluminum alloy and the non-metallic portion is formed from a polymer. 
     In one approach, the first environment is the out-of-doors and the second environment is interior to the building envelope. 
     In one approach, both the frame structure and the surround are formed from a plurality of elongated elements attached together at the ends thereof. 
     In one approach, the adaptor has a raceway distal to the opposed arms for receiving a trim cover. 
     In one approach, a method for assembling a window for an opening through a building envelope, includes obtaining a plurality of elongated frame elements made from aluminum alloy extrusions and attaching them together at the ends thereof to form a frame structure; obtaining a plurality of elongated box sections made from aluminum alloy extrusions and having an outward facing channel; attaching the plurality of elongated box sections together at the ends thereof to form a first portion of a window surround; obtaining a glazing panel; obtaining a plurality of L-shaped ledge portions made from polymer and having insertion legs; inserting the insertion legs of the ledge portions into corresponding channels of the box sections to form a surround capable of embracing the periphery of the glazing panel and inserting the glazing panel into the surround to form a vent assembly; attaching the frame structure to the building, framing the opening; and attaching the vent assembly to the frame structure. 
     In one approach, a method for assembling a window for an opening through a building envelope, includes obtaining a plurality of elongated frame elements made from aluminum alloy extrusions and having an attachment bead disposed on a surface thereof; attaching the elongated frame elements together at the ends thereof to form a frame structure; obtaining a plurality of polymer adaptors having a coupling head; attaching the adaptors to corresponding ones of the frame elements by snap-fitting the coupling head over the attachment bead to form a frame assembly; obtaining a plurality of elongated vent surround sections made from aluminum alloy extrusions; attaching the plurality of elongated vent surround sections together at the ends thereof to form a vent surround; obtaining a glazing panel; inserting the glazing panel into the vent surround to form a vent assembly; attaching the frame structure to the building, framing the opening; and attaching the vent assembly to the frame structure. 
     In one approach, a vent surround, includes a box portion made from a plurality of metal sub-sections connected at the ends thereof and a non-metallic ledge with a plurality of sub-sections that attach to the sub-sections of the box portion, the sub-sections of the box portion each having an elongated channel and each of the sub-sections of the non-metallic ledge having an L-shaped cross-sectional shape with an insertion leg capable of being received in the elongated channel, the non-metallic ledge having a lower thermal conductivity than the metal box portion, the non-metallic ledge being proximate a first environment on a first side of the building envelope and the metal box portion being proximate a second environment on a second side of the building envelope. 
     In one approach, a frame structure couplable to a building to frame an opening through the building envelope includes a metallic base portion that couples to the building; a metallic extension portion extending perpendicular to the building envelope proximate the opening; a non-metallic adaptor capable of being coupled to the extension portion, the non-metallic adaptor having a lower thermal conductivity and position proximate a first environment on an exterior of the building envelope and the metallic base and extension portions having a higher thermal conductivity and positioned proximate a second environment on the interior of the building envelope. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure, reference is made to the following detailed description of exemplary embodiments considered in conjunction with the accompanying drawings. 
         FIG. 1  is elevational view of a fragment of a window system. 
         FIG. 2  is a cross-sectional view of a sill of the window system of  FIG. 1  taken along section line  2 - 2  and looking in the direction of the arrows. 
         FIG. 3  is a cross-section like  FIG. 2 , but of a window system in accordance with an embodiment of the present disclosure. 
         FIG. 4  is a perspective view of a ledge portion of a vent surround. 
         FIG. 5  is a side view of the ledge portion of  FIG. 4  and alternative ledge portions. 
         FIG. 6  is a cross-section like  FIG. 2 , but of a window system in accordance with another embodiment of the present disclosure. 
         FIG. 7  is an enlarged portion of  FIG. 3 . 
         FIG. 8  is a perspective view of a frame adaptor in accordance with another embodiment of the present disclosure. 
         FIG. 9  is a series of cross-sectional views of frame adaptors in accordance with embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       FIG. 1  shows a window system  10 , e.g., for a façade of a commercial building, such as a multi-story high rise building. Using conventional terminology, each window unit  12  of the window system  10  has a head  14 , a sill  16  and jambs  18 . The jambs  18  between adjacent window units  12  may be designated mullions. Some or all of the window units  12  may be hinged to be opened and closed for ventilation. For applications where there is no protective roof or awning overhang, the window unit would typically open at the sill  16 . In other applications, the window units  12  may open at the head  14  or at the jambs  18 . 
       FIG. 2  is a cross-sectional view of a window unit  12  of  FIG. 1  at the sill  16  in accordance with the prior art. A compound structural beam  20  having an interior portion  20 I and an exterior portion  20 E separated by a thermal break  22  and bridged by a plate  24  is a component of the building structure, e.g., a storefront. The beam  20  is attached to the superstructure of the building and serves as the mounting surface for a window frame element  26 , which may be fastened to the beam  20  by screws  28  or other fasteners extending through a peripheral portion  26 P. A plurality of attached frame elements  26 , e.g., four (at the head, sill and jambs) may be used to define a rectangular frame for the window unit  12 . The frame elements  26  may be L shape in cross section, a limiting portion  26 L limiting the motion of a vent  30  in the direction of the interior I. The vent  30  is the portion of the window unit  12  that typically contains an optically transparent/translucent glazing unit  32 , e.g., one or more (e.g., double or triple glazed windows) glass or plastic panels  32 A,  32 B separated by an intermediate spacer  34 , defining a space  36 , which may contain air, an inert gas or radiation/convection barrier films. A peripheral setting block  38  is attached to the edge of the panels  32 A,  32 B to protect glazing unit  32  from being damaged by direct contact with vent surround ledge portion  40 L. The vent surround  40  may be made from a plurality of extrusions that are coupled together to embrace the glazing unit  32  at all sides thereof, e.g., four sides for rectangular glazing panels  32 A,  32 B. For example, the vent surround  40  may be formed from four aluminum alloy extrusions that are miter cut at the ends thereof and then assembled, by welding, staking and/or with brackets and/or fasteners. The vent surround  40  may have a boxed portion  40 B to impart structural rigidity and an integrally formed ledge portion  40 L that surrounds the glazing unit  32 . The glazing unit  32  may be secured to the vent surround  40  by the use of a silicone sealant  42 A,  42 B. 
     A first seal  44 , which may be formed from an elastomer is attached to the vent surround  40  and reduces weather infiltration between the window frame elements  26  and the vent surround  40 . A second seal  45  attached either to the frame elements  26  or the vent surround  40  (but not both) may aid in preventing weather intrusion into the interior I. The seals  44  and  45  allow the vent surround  40  to be moved relative to the frame elements  26 , such that the window unit  12  may be opened and closed, while decreasing weather (air and water) infiltration. 
     An aspect of the present disclosure is the recognition that the vent surround  40  is a conduit for heat transfer from the environment E exterior to the window unit  12  to an environment I interior to the window unit  12  (inside a building). 
       FIG. 3  is a cross-section of a window unit  112  in the sill  116  area like the window unit  12  of  FIG. 2 , but in accordance with an embodiment of the present disclosure. The window unit  112  features a composite vent surround  140  featuring a boxed portion  146  made, e.g., from aluminum alloy to impart structural rigidity, and an independently formed ledge portion  148  made, e.g., from a polymer, such as rigid PVC or glass reinforced nylon, having a lower heat conductivity than aluminum. Ledge portion  148  has an insertion leg  150  which may have a plurality of engagement ribs/barbs  152  (See  FIGS. 4 and 5 ) that are disposed at an angle B relative to the insertion leg  150 , the angle facilitating insertion into and resisting removal from a channel  146 C in the box section  146 . The insertion leg  150  may be retained in the slot  146 C by friction fit, the action of the ribs/barbs  152  and/or an adhesive. As in the window unit  12  described above, a plurality, e.g., four, vent surrounds  140  with associated box portions  146  and ledge portion  148  may be assembled together to surround and retain the glazing unit  130 . The aluminum alloy boxed portions  146  may be connected by welding, brackets and fasteners, etc., thereby forming a rigid framework for mounting the ledge portions  148 , which may also be attached together, e.g., by screws or rivets. The glazing unit  130  may be adhered to the box section  146  by a sealant  142 A and the window unit may also feature a a peripheral setting block  142 B (shown in dashed lines tofor eas of illustration). 
       FIGS. 3 ,  4  and  5  shows that the ledge portion  148  may be provided with a self-centering plateau  154  that matingly engages corresponding surfaces of the channel  146 C to automatically establish a pre-selected relative orientation between the ledge portion  148  and the box portion  146 . A hinge hardware locating nub  155  provides a reference surface for uniform and precise hinge hardware positioning when hinges are used and acts in conjunction with insertion stop  157  to limit insertion and stabilize the ledge portion  148  relative to the box portion  146 . The ledge portion  148  has a plurality of thermal barrier fingers  159  made, e.g., from high durometer, soft PVC or other flexible materials, that may bear against or pass close to an opposing surface to reduce the passage of air and consequent transfer of energy. As explained more fully below, the window unit  112  embodiment shown in  FIG. 3  features a composite frame element  126  with a bifurcated coupling bead or barb  168  upon which a frame extension/adaptor  170  may be received and retained. The adaptor  170  abuts against (and displaces) the first finger  159 F to effect a weather seal. The fingers  159  may be spaced to minimize thermal conduction, as explained further below. 
     The ledge portion  148 , which may be considered a first ledge portion  148 , has an integrated screw port  156  for receiving screws S (one screw head shown diagrammatically in dotted lines) extending through an adjacent second ledge portion  148  to hold the adjacent second ledge portion to a first ledge portion  148  via a screw screwed through the second ledge portion and extending into the screw port  156 . For example, if a first ledge portion  148  (as depicted in  FIG. 3 ) is disposed along the sill then a second ledge portion  148  disposed along the adjacent jamb may be tightly attached to the sill ledge portion  148  via a screw that extends through the jamb ledge portion  148  and into the screwport  156  of the sill ledge portion  148 . A flat offset area  158  allows the first and second ledge portions  148  to seat flush to one another and defines a ledge that prevents relative translational movement when the screw S is tightened. 
     An integral raceway  160  accommodates a variety of trim covers  162  or other modular parts in snap-fit relationship. The trim cover  162  covers the adjacent edge of the glazing unit  130  and also extends down to reduce weather infiltration. The box section  140  also features a raceway  164  for receiving a bead seal  166  that seals against limiting portion  126 L of window frame element  126 . The frame element  126  has a bifurcated coupling bead  168  at an end thereof for coupling to a selected adaptor  170 , as described more fully below. The adapter  170  may be selected to interact advantageously with a given window unit installation environment (to reduce heat transfer/weather infiltration) and also to accommodate different types of glazing units  130 , e.g., double and triple glazed.  FIG. 4  shows that the ledge  148  may have a surface  148 S from which the fingers  159  extend with a front-to-back taper angle alpha of e.g., 1 degree. The taper angle may be used to shed water away from the window unit  112  when the ledge portion is used at the head  14 , i.e., with the fingers  159  pointed up. Alternatively, the extending portion  148 E may be molded at an angle less than 90 degrees relative to the insertion leg  150 . 
       FIG. 5  shows that different ledge portions  148 ,  148 A,  148 B,  148 C with different dimensions and number of fingers  159 ,  159 A,  159 B,  159 C may utilize the same features, e.g., insertion leg  150 , plateau  154 , hinge nub  155  and insertion stop  157 , that allow coupling the ledge portions  148 ,  148 A, etc. to the same type of box portion  146 . In a similar manner, the box portion  146  may be varied in dimensions but have a consistently shaped and dimensioned channel  146 C that may couple in a consistent manner to one or more different ledge portions  148 . The consistent coupling features lead to modularity, i.e., multiple parts with variations optionally coupling to multiple parts with variations, in the same manner. Ledge portion  148  with fingers  159  (all in solid lines) is an example of a ledge portion  148  that may be suitable for use with a double glazed glazing unit  130  used in a storefront application. The dimensions of ledge portion  148  may be varied, e.g., to be suitable for use in a curtain wall application by extending the length of fingers  159 A, yielding a variant ledge portion  148 A. Ledge portion  148 B with fingers  159 B (in dashed lines) may be suitable for a triple glazed storefront window. For a curtain wall application, the fingers  159 B can be lengthened, as shown by  159 C to yield a variant ledge portion  148 C. Notwithstanding the variations in dimensions of the ledge portions  148 ,  148 A,  148 B, the tooling used to process an elongated extrusion, e.g., eighteen feet in length, into assemblable portions of a given length for surrounding a given glazing unit  130 , may remain consistent. For example, a cutter (not shown) used to remove a length, e.g., 4.25 to 5.0 inches of the insertion leg  150  at either end of the horizontal lengths of the ledge portion  148  to permit mating with the vertical lengths, may be the same for each variant of the ledge portions  148 A,  148 B and  148 C. Similarly, tools for miter cutting, punching or drilling the holes for passing screws S, etc. may be standardized for a variety of ledge portions with different dimensions. 
       FIG. 6  is a cross-section of a window unit  112  in the sill  116  area like the window unit  12  of  FIG. 3 , but with a different type of adaptor  270 . As before, the window unit  112  features a composite vent surround  140  featuring a boxed portion  146  made, e.g., from aluminum alloy to impart structural rigidity, and an independently formed ledge portion  148  made, e.g., from a polymer, such as rigid PVC or glass reinforced nylon, having a lower heat conductivity than aluminum. The composite frame element  126  has a bifurcated coupling bead or barb  168  upon which a frame extension/adaptor  270  may be received and retained. The adaptor  270  is made from a polymer, such as rigid PVC or glass reinforced nylon, having a lower heat conductivity than aluminum and abuts against (and displaces) the first finger  159 F to create a weather seal. An extension portion  270 E extends below and proximate to the ends of fingers  159 A,  159 B and trim cover  162  to further improve weather resistance. Optionally, the fingers  159 A,  159 B may contact the extension  270 E. 
       FIG. 7  shows the coupling bead/barb  168  with dual lead-in surfaces  168 A,  168 B that meet negatively cambered surfaces  168 C,  168 D at a cusp or point. The adaptor  170  has a coupling portion  171  having a pair of opposed arms  170 A 1  and  170 A 2  with complementary, mating surfaces, viz., sloped lead-in surfaces  170 B 1 ,  170 B 2  that meet positively cambered surfaces  170 C,  170 D at a rounded point. The lead-in surfaces  168 A,  168 B and  170 B 1 ,  170 B 2  facilitate inserting the barb  168  into the cavity  170 E of the coupling portion  171 , the adaptor  170  resiliently bending and then snapping back into a rest configuration when the barb  168  is fully inserted into the cavity  170 E in the engaged position. When in the engaged position, the surfaces  168 C,  168 D and mating surfaces  170 C,  170 D hinder dis-engagement and ensure a positive locking interaction with minimal rotation. Central recesses  168 F and  170 F accommodate a bead sealant (not shown) that is applied prior to assembly to aid in preventing water infiltration. Surfaces  170 B 1 ,  170 B 2  closely parallel surfaces  168 G,  168 H when the adaptor  170  is coupled to the coupling bead  168  to aid in sealing the coupled adaptor  170  and coupling bead  168 . 
       FIG. 8  shows the adaptor  270  of  FIG. 6  prior to connection to a coupling bead  168  of window frame element  126 . An extension portion  270 E extends from coupling portion  271 . 
       FIGS. 9A-9F  show a series of frame adaptors  370 ,  470 ,  570 ,  670 ,  770 ,  870 , e.g., that may be used in the context of a curtain wall window system.  FIG. 9F  shows a perspective view of the frame adaptor  870 . The adaptors  370 ,  470 ,  570 ,  670 ,  770 ,  870  are varied in dimensions and have various extensions, e.g.,  370 E,  470 E,  570 E,  670 E,  770 E,  870 E with different dimensions and features, e.g., the positioning of the screw ports  356 - 856  and wings  380 ,  480 ,  680 ,  780 , but have a common configuration with respect to coupling portion  371 ,  471 ,  571 , etc., which have coupling arms, e.g.,  370 A 1 ,  370 A 2 ,  470 A 1 ,  470 A 2 , allowing the different adaptors to be attached to the same types of coupling bead  168  ( FIG. 7 ). 
     While the foregoing describes composite vent surrounds  140  and composite window frames  126  with metal and plastic components explained relative to use in a sill  116 , the head  14 , and jambs  18  may be similarly formed from composite elements to reduce heat transfer and weather infiltration. 
     It will be understood that the embodiments described herein are merely exemplary and that a person skilled in the art may make many variations and modifications without departing from the spirit and scope of the claimed subject matter. For example, while the present disclosure has been expressed relative to windows, the disclosed concepts could be applied to doors, non-window vents and other building structures. All such variations and modifications are intended to be included within the scope of the appended claims.