Metal window construction
BACKGROUND OF THE INVENTION 
     The present invention relates to metal window constructions and particularly those used in detention or correctional facilities. It further relates to methods for manufacturing and installing windows. 
     There are two basic known approaches for constructing windows in correctional facilities so that they cannot be later removed. One approach grouts the windows in with brick and mortar; that is, the entire window frame is cased or blocked into place. Damage to the glass from the abrasive nature of adjacent material during installation often results from this approach and therefore field glazing after installation is often necessary. Another approach welds the window in and attaches an access cover over it. In other words, the window frame is placed in the window opening against an embed and welded into place, and the window is then glazed from the exterior. This is a labor intensive installation process, however, especially for multi-level facilities. By field welding the window frame to an embed in the wall opening, the hazard to the glass from extreme heat and weld splatter is high, which necessitates field glazing. 
     Many windows are designed so that the fasteners that hold them in place are located in the glass pocket. Thus, the glass must be installed at the job site after the installation of the frame. Most manufacturers and constructors in the steel window business do not have the expertise or exercise sufficient care in the installation and handling of panes of glass. Scratches or breakage to the glass during handling and installation are thus common. 
     SUMMARY OF THE INVENTION 
     Accordingly, a principal object of the present invention is to provide an improved secure window construction suitable for use in detention facilities and the like. 
     Another object of the present invention is to provide an improved window assembly design which can be easily installed with minimum and low-skill field labor. 
     A further object of the present invention is to provide an improved window installation technique which minimizes the likelihood of damage to the glass and thus eliminates the need for field glazing. 
     A still further object of the present invention is to provide an improved all-metal security window construction which is resistant to forced entry or exit, depending on the orientation of the window. 
     Directed to achieving these objects, a window construction including a metal subframe assembly, adapted to be anchored into a window opening, and a factory-glazed and welded metal frame assembly is herein provided. The frame assembly is pushed or inserted into place in the anchored subframe assembly conveniently from inside of the building. When pushed in, clips integral with the subframe (or frame) assembly engage in notch blocks integral with the frame (or subframe) assembly, automatically center the frame assembly in the subframe assembly, lock it therein, and self-adjust the window construction to provide a tight fit. No welding or other significant field assembly is required. The locked clip is inaccessible within the structure of the window, thereby permanently and immovably securing the frame assembly in and to the subframe assembly. An alternative embodiment provides a top locking bar which when removed allows the frame assembly to be lifted, the (wedge) clip disengaged and the frame assembly removed for servicing or replacement. Other alternatives include thermal break, all-aluminum and pry-proof versions. 
     Other objects and advantages of the present invention will become more apparent to those persons having ordinary skill in the art to which the present invention pertains from the foregoing description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view illustrating a window construction of the present invention. 
     FIG. 2 is an exploded perspective view of the window frame assembly of the window construction of FIG. 1. 
     FIG. 3 is an exploded perspective view of the subframe assembly of the window construction of FIG. 1. 
     FIG. 4 is a cross-sectional view of a first alternative anchoring means for the subframe assembly of the window construction of FIG. 1. 
     FIG. 5 illustrates a second alternative anchoring means of the invention. 
     FIG. 6 illustrates a third alternative anchoring means. 
     FIG. 7 is a perspective view of the subframe assembly of the window construction of FIG. 1 illustrating an assembling step therefor. 
     FIG. 8 is a perspective cut-away view showing the subframe and frame assemblies of the window construction of FIG. 1 oriented prior to engagement of the latch clip assembly thereof. 
     FIG. 9 is a view similar to that of FIG. 8 illustrating the orientation of the latch clip assembly when engaged. 
     FIG. 10 is a cross-sectional view, through a frame jamb, of a portion of the window construction of FIG. 1. 
     FIG. 11 is a view similar to that of FIG. 10 illustrating a thermal break window construction embodiment of the present invention. 
     FIG. 12 is a view similar to that of FIG. 10 illustrating an all-aluminum embodiment of the present invention. 
     FIG. 13 is a view similar to that of FIGS. 11 and 12 and illustrating an all-aluminum, thermal break embodiment of the present invention. 
     FIG. 14 is an exploded perspective view illustrating an upper portion of an alternative removable window construction of the present invention. 
     FIG. 15 is a cross-sectional view of the window construction of FIG. 14. 
     FIG. 16 is a view similar to that of FIG. 10 illustrating a forced entry resistant window construction of the present invention. 
     FIG. 17 is a view similar to that of FIG. 11 illustrating a forced entry resistant, thermal-break window construction of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
     A window construction of the present invention is illustrated for example in FIG. 1 generally at 20. A number of embodiments of window construction 20 are disclosed herein and corresponding parts are designated with the same reference numerals. Also, the inside (indoors) and the outside (outdoors) are shown by reference numerals I and O, respectively. The window construction 20 comprises a subframe assembly shown generally at 22 and secured by an anchoring system shown generally at 24 in an opening in a wall 26. A window frame assembly 28 is secured to and inside of the subframe assembly 22 by a latch clip assembly, shown generally at 30 in FIG. 9 for example. 
     The frame assembly 28 is manufactured and assembled conveniently at the factory. As shown in FIG. 2, the frame assembly 28 comprises four frame pieces--two jambs 32, a head 36 and a sill 38. Each piece is formed of sheet metal, a minimum (for detention products) of twelve-gauge hot rolled steel sheared to the appropriate size and formed into the desired shape. The frame assembly pieces are welded together, and the four notch blocks 40 of the latch clip assembly 30 are tack welded into place. The four notch blocks 40 can be tack welded into the subframe assembly 22 when the latch clips 70 are tack welded into the window frame assembly 28. The frame is match drilled and tapped to facilitate the attachment, with machine screw fasteners 42, of the glazing stop shown generally at 44. 
     The glazing stop 44, comprising a pair of jambs 48, a head 52 and a sill 54, retains the glass, glazing or any suitable opaque material 55 in place in the welded frame. The frame assembly 28 is thus &#34;factory glazed,&#34; that is, the glass is installed in the window frame at the factory. Sealing material 56 is sandwiched between the glass 55 and the frame assembly 28 on either side of the glass, and a preferred material is the &#34;Tremco 440 Pre-Shimmed Glazing Tape.&#34; Standard glazing rolled-in extruded vinyl or rubber seal can also be used in some cases. A shim 58 is placed at the edge of the glazing 55 adjacent the angle stop 44. Removable protective plastic films 60 placed over the glazing 55 on both sides thereof prevent minor scratches and other minor damage to the glazing during handling and installation thereof. 
     The subframe assembly 22 is illustrated in FIG. 3 and similarly comprises a pair of opposed jambs 62, a head 66 and a sill 68. Each subframe piece is formed of sheet metal, a minimum of twelvegauge hot rolled steel sheared to the appropriate size and formed to the desired shape. The pieces are welded together, and similar to the frame assembly 28, the subframe assembly 22 is full welded at its corners and dressed smooth for painting. The four (or more) latch clips 70 of the latch clip assembly 30 are tack welded to the window frame assembly 28, for example, as the notch blocks 40 are tack welded to the subframe assembly 22. The welded subframe and window frame assemblies 22, 28 are then primed, finish painted and packaged separately at the factory and then transported to the construction site. 
     All installation work of the window construction 20 is done conveniently and safely from inside of the building as will be understood from this disclosure. The subframe assembly 22 is set into the wall 26 when the wall is being constructed and anchored therein by the anchoring system 24. It can be anchored into any wall material such as precast concrete, block or CMU. Wall anchors 72 such as are shown in FIG. 1 can be used as the anchoring system 24 for a CMU block 74 wall, and the subframe assembly 22 has slots 76 on its sides to allow for variances in the block and the mortar. A bead of caulk is run on both sides of the subframe assembly 22 to form a seal between the wall 26 and the subframe assembly. This is done prior to the insertion of the window frame 28 which eliminates additional exterior caulking. 
     An alternative anchoring system 24 is shown in FIG. 4 wherein a stud anchor 78 welded to the subframe assembly 22 is cast into place in the wall 26. Another alternative is illustrated in FIG. 5 wherein a strap type of anchor 80 is welded to the subframe assembly 22 and cast into place. Referring to FIG. 6, a further alternative embodiment wherein an expansion anchor or bolt 82 mounts the subframe assembly 22 to (a rough opening in) the precast or block is shown. 
     As best illustrated in FIG. 7, glazing tape 84 is rolled from a roll 86 into place overlapping at the corners on inside surfaces of the outermost ledge 88 of the subframe assembly 22. A small bead of caulk 90, approximately one-eighth of an inch wide, is applied from a caulk gun 92 to the exposed or innermost edge of the tape 84. Tape 84 and caulk 90 provide a good seal between the subframe assembly 22 and the frame assembly 28. Any protective coating 60, such as shown in FIG. 2, is removed from the exterior side of the glazing 55. The frame assembly 28 is then set into the sill 68 of the subframe assembly 22, making sure that the glazing tape 84 and caulk 90 at the sill are not displaced. The frame assembly 28 is then pushed (from the inside of the building) into the subframe assembly 22 until it bottoms out and all of the locking or latch clips 70 are engaged. The engaged latch clips 70 spring back to locate on one of the several notches 94 on their respective notch blocks 40. As the clips 70 are locked into any one of the notches 94 of their respective notch blocks 40, any slack from manufacturing and/or building tolerances is automatically taken up and the latch clip assembly 30 self-aligns automatically. Also, the glazing tape and the caulk compress, and since the mating parts (notch blocks 40) for the locking clips are notched (notches 94), the window frame cannot be removed (see the embodiments of FIGS. 14 and 15, however) and will not rattle. Any touch-up work, such as the removal of the interior protective layer 60 on the glazing 55, touch-up painting and caulking, can then be done. 
     A number of variations on the general concept of this invention are possible. One of them is the thermal break embodiment illustrated in FIG. 11. Thermal break material 100, according to this embodiment, is held between flanges or frames 102, 104 of the inside or interior portions of the frame assembly and the outside or exterior portion of the frame assembly and secured therebetween by threaded fasteners 106. The thermal break embodiment thus uses inner and outer frames 102, 104 separated by a non-conducting material 100. Generally, any high impact plastic can be used for the thermal break material 100, and an example thereof is a relatively inexpensive phenolic such as &#34;Garolite&#34;. The material 100 is first cut into strips and holes formed therethrough to allow the bolts or screws 106 and insulating washers 108 to sandwich it in between the inner and outer portions of the frame. It is seen in FIG. 11 that the bolt 106, which clamps the thermal break material 100 between the inner and outer frames 102, 104, is oriented so that its head is away from the interior. 
     An example of an all-aluminum version is shown in FIG. 12 wherein roll-in glazing vinyl member 110 is positioned between the interlocking glazing stop 112 and the glazing 55. The steel latch clip 70 is held at its mounted end in a groove forming structure 116. The notch block 40 is also formed as a single piece with an edge or end of the frame assembly 22. The non-detention all-aluminum design can be used in commercial or heavy commercial/low security applications. Thus, the locking clip mechanism concept is conceptually the same for this version as the detention embodiment but the materials are different. 
     An all-aluminum thermal break version of the invention, which is in a sense a hybrid of the embodiments of FIGS. 11 and 12, is shown in FIG. 13. Similar to some of the previously-discussed embodiments it includes a glazing 55, glazing tape 56 and a vinyl seal on opposite sides of the glazing, a rubber shim block 58 at the end of the glazing, a window frame 28, an integral notch block 40 having notches 94, a latch clip 70 held at one end in the groove 116 of the subframe 22 and at its opposite free end engageable in one of the notches, a glazing stop 112 and thermal break material 100. 
     When it is desirable in certain applications to later remove the window frame assembly for cleaning or reglazing, an alternative embodiment of the present invention can be used as shown in FIGS. 14 and 15. The latch clip assembly 120 for this embodiment includes wedge clips 122 welded to the subframe assembly 22 and engageable in notches 124 formed in the frame assembly 28, when the frame assembly is inserted therein. The frame assembly 28 is held removably in place with a lock bar 126 secured by security fasteners 128 in the frame assembly 28. When secured therein, the frame assembly 28 cannot be lifted off of the wedge clips 122 and the window frame assembly cannot be removed from the subframe assembly 22. In other words, the bar 126 is bolted by fasteners 128 to the head of the window to prevent it from being lifted off the clips 122. An access panel 130 is secured by screws 132 then over the lock bar 126. 
     When the metal window constructions of the present invention are used in security installations, further design features can be provided to ensure that pry bars or other tools (not shown) cannot be inserted into the various window joints and the window thereby pried apart or open. These pry-proof features are illustrated in FIGS. 16 and 17 as applied to the window constructions of FIGS. 10 and 11, respectively. As shown in FIGS. 16 and 17, a centering clip 136 can be secured to and inside of the subframe assembly 22, but not in line with the latch clip. The centering clip 136 prevents the latched window from being pried from side-to-side. A flange 138 at the inside end of the subframe assembly 22 and inside of the frame assembly 28 blocks entry of a pry bar at the juncture, inside of the building, of the frame and subframe assemblies. A stiffener plate 140 can be positioned at an angle relative to and inside of the frame assembly. This stiffener plate 140 for the FIG. 10 embodiment can have an angled portion, as shown in FIG. 16 at 142, defining a metal barrier to further deter pry bar instrusion. 
     In cases where high security is paramount, the space between the subframe and window frame can be grout filled at the job site to prevent any and all intrusion into the metal portion of the window. This is easily accomplished by providing fill holes at the top of the window frame, such that, after the window frame has been set into the subframe and finish caulked, grout can be forced into the space between the window frame and subframe by a grout pump or similar device. 
     Other variations of the window construction of the present invention involve different sizing of the components or utilizing different materials. Tool resisting or mild steel security bars (not shown) can also be made as integral parts of the window frame. Aluminum, steel or glazing stops and variations in the weep hole arrangement are also within the scope of this invention. The clip, or clip and notch block, can be run continuously instead of the relatively short, three-inch latch assembly illustrated herein, which would make the present window even more secure. 
     The present metal window construction thus has a number of unique features and advantages. Its design allows the window assembly to be set from inside of the building thereby eliminating the need for most outside labor. The window frame assembly self-centers in the subframe assembly and self-adjusts to provide a tight fit as it is being installed. The field labor and special skills required to install this window are minimal, since the subframe assembly is factory welded, assembled and glazed. Damage to the glass from scratches, weld splatter or breakage is thus minimal. According to principal embodiments hereof, the frame latching mechanism is captured inaccessible within the window construction, permanently affixing the window pane to and in the building wall, thereby making it ideal for use in security environments. 
     From the foregoing detailed description, it will be evident that there are a number of changes, adaptations and modifications of the present invention which come within the province of those skilled in the art. However, it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof is limited solely by the claims appended hereto.