Abstract:
A reduced tolerance window support bracket assembly is disclosed. The bracket includes a hinge with a vent bar having apertures to accept fasteners for engaging the hinge to a window sash. The apertures and the fasteners are configured to provide that the play between the window sash and a frame is optimized, thus avoiding the extremes of possible leakage and excessive pressure on a weather-strip.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to window supporting brackets which are arranged to support a window for pivotal movement about either a vertical or a horizontal axis. More particularly, the present invention relates to a supporting bracket assembly providing an optimized adjustment tolerance.  
         BACKGROUND OF THE INVENTION  
         [0002]    Windows are a significant source of heat loss from buildings. Given the necessity to save costs and conserve energy, increasing attention is directed to improving the efficiency of windows. Much energy can be saved by such strategies as providing sealed double-paned windows and using low-E glass, much of the conservation realized thereby can be vitiated by inadequately sealed windows. While this is not a usually an issue with fixed windows, those that are intended to be opened lend themselves to the provision of more effective seals.  
           [0003]    A common type of window consists typically of a rectangular frame set into a building wall and a corresponding pivotally movable vent. Such windows typically have supporting brackets to permit pivotal movement of the vent about a vertical axis or a horizontal axis, and are also adapted to be connected between a conventional window frame and window sash, whether these structures be formed of metal, wood, PVC, or other structural material. The brackets are typically arranged to cause the pivotal axis of the window to move to and from the window frame so that when the window is open, both surfaces are accessible from the inner side of the window.  
           [0004]    As in other windows, weather-stripping must be interposed between the vent and the frame in order to provide an effective seal when the window is closed. The quality of the seal depends on a number of factors such as the clearance between the vent and the frame in terms of its actual value and the tolerance or “play” allowed, and the physical properties of the seal material. It is assumed that the weather-stripping is compliant enough to yield to pressure exerted by the vent. There must be sufficient play to allow for variability of the weather-stripping. For an optimum seal, the elements of the window must be in the closest possible contact with the weather-stripping while simultaneously not exerting excessive pressure thereon, which could lead to sticking.  
           [0005]    U.S. Pat. No. 5,898,977. to Muir, discloses a supporting bracket or stay which can be used on a window. Although the supporting bracket disclosed therein substantially precludes sash play to an extent found in other prior art, the tolerance is nevertheless not optimized.  
           [0006]    Accordingly, there is a need to provide a mechanism for optimizing the clearance between the vent and the frame, and the allowable play therebetween, so that the clearance is small enough to minimize leakage of air or water through the window, while there is enough play to avoid excessive pressure on the weather-stripping, which could cause sticking problems.  
         SUMMARY OF THE INVENTION  
         [0007]    A preferred embodiment supporting bracket assembly of the present invention includes a four bar hinge substantially as disclosed in U.S. Pat. No. 5,898,977, and a fastener configured to provide optimum positioning of the hinge relative to the window sash. The hinge includes a track for mounting to a frame; a vent bar for attaching to a window sash, the vent bar being hinged for movement on both sides of the centerline of the track, and having a centerline parallel and substantially in line with the centerline of the track when the supporting bracket is in a closed position; and structure, during an opening operation, for preventing the vent bar from crossing the centerline of the track in a direction opposite a direction of opening. The supporting bracket of the preferred embodiment is “non-handed”, that is, may be utilized on opposite sides of a window.  
           [0008]    In any contemplated embodiment, a pair of apertures is provided in the vent bar, for accepting the fastener. The clearance the aperture provides between the vent bar and the fastener determines the amount of tolerance in the positioning of the vent bar relative to the sash and, therefore, how well the window seals against weather-stripping which is typically present.  
           [0009]    The foregoing and other features and advantages of the invention will be more readily understood and fully appreciated from the following detailed description, taken in conjunction with the accompanying drawings.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 shows a side perspective view of a fully assembled supporting bracket in a closed position.  
         [0011]    [0011]FIG. 2 shows a top plan view of the supporting bracket of the present invention in an open position.  
         [0012]    [0012]FIGS. 3A and 3B show a perspective view of a portion of a vent bar in the process of engagement with a window sash using a fastener.  
         [0013]    [0013]FIG. 4A shows a top plan view of a portion of a portion of the vent bar.  
         [0014]    [0014]FIG. 4B shows a top plan view of the fastener.  
         [0015]    [0015]FIG. 5 shows a top plan view of the mounting set-up of the window supporting bracket.  
         [0016]    [0016]FIG. 6A and 6B represent schematically the play of a window sash relative to the vent bar. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]    As shown in FIGS. 1 and 2, a supporting bracket  10  of the present invention may be positioned in a closed position or one of many open positions. A window sash  122  is frictionally restrained in any angular position to which the supporting bracket  10  is moved. This frictional restraint is provided by the friction between the various elements of the supporting bracket  10   
         [0018]    The supporting bracket  10  may be positioned on any side of a window, and is generally provided in pairs. Each bracket  10  in the pair of brackets utilized to support a window includes a track member  12  having folded side flanges  14 . The track member  12  is secured by screws (not shown) to a window frame  120 , preferably with one end  26  of the track member  12  adjacent a corner of the window frame  120 .  
         [0019]    Mounted on the track member  12  is a slide  16  having side flanges  18  which fit under and are retained by the side flanges  14 . The slide  16  is preferably a solid brass shoe for smooth, long-lasting performance. The slide  16  is provided with a shallow raised portion forming a cavity confronting the track  12 .  
         [0020]    The slide  16  is slidable between the end  26  of the track member  12 , adjacent the comer of the window frame  120  and a position near the opposite or extended end  24 . The end  24  of the track remote from the comer of the window frame  120  may be provided with a raised boss (not shown) extending to a level flush with the upper surfaces of the side flanges  14 . The boss is provided with a pivot pin or rivet  30 .  
         [0021]    As best seen in FIGS. 3A and 3B, a substantially flat vent bar  34  is secured to the confronting side of the window sash  122  by fasteners such as screws  202  passing through mounting apertures  200  which are preferably elongate in the direction of the vent bar  34 .  
         [0022]    When the window sash  122  is in its closed position within the window frame  120 , the bar  34  overlies or confronts the track  12  with one end  36  adjacent the end  26  of the track  12  disposed in the comer of the window frame  120 . Near this end  36  of the bar  34 , there is provided a downward offset  38  and pivot pin or rivet  40 . A short link  42  is pivotally connected between the pivot pin  40  and a pivot pin  44  provided on top of the slide  16 .  
         [0023]    The bar  34  is provided with a second pivot pin  46 . A strut  48  extends between the pivot pin  46  and the pivot pin  30  at the remote end  24  of the track  12 . The pivot pin  46  is so located that when the bar  34  is in superposed relation with the track  12 , the strut  48  is interposed between the track  12  and bar  34  and is in alignment with the bar  34 . This is likewise true of the link  42 .  
         [0024]    A portion of the strut  48  is offset upwardly as indicated by  50 . Within the length of the upwardly offset portion is a pivot pin  52 . A brace  54  extends between the pivot pin  52  and the pivot pin  44  of the slide  16 . The length of the link  42 , between the pivot pins  40  and  44  and the length of the brace  54  between the pivot pins  44  and  52  combined are equal to the portion of the strut  48  between the pivot pins  52  and  46 , plus the portion of the bar  34  between the pivot pins  46  and  40 . The pivot pins  40 ,  44 ,  52 , and  46  define a four-sided figure. The bar  34 , link  42 , strut  48 , and brace  54  are preferably all made from stainless steel and are preferably provided with rounded edges. Together, the four elements  34 ,  42 ,  48 , and  54  define what is known in the industry as a “four bar hinge”. Although only four bars,  34 ,  42 ,  48 , and  54  are disclosed, it should be understood that additional bars may be included for heavier windows, such as a cross-link connecting the brace  54  to the bar  34 .  
         [0025]    It is desirable that the window sash  122  fit tightly against the window frame  120  when the window sash  122  is closed, but not so tightly as to excessively compress the weather-stripping. To this end, once the widow sash  122  and vent bar  34  are secured together by the screws  202  as indicated earlier, the alignment of the vent bar  34  and the window sash  122  is defined by the relationship between screws  202  and the mounting apertures  200 , which have a length and a width, the latter being as indicated as W in FIG. 4A. As can be appreciated, the bar  34  can be translated along the sash  122  as permitted by the length. However, any sideways displacement is limited by the magnitude of the difference (W−T), where T is the screw diameter as indicated in FIG. 4B. It is most typical to use in such applications a no. 10 screw, for which T is nominally 0.185″ (4.70 mm).  
         [0026]    In the present invention, W is selected to be no greater than 0.195″ (4.95 mm); in other words, the sideways clearance of the screw  202  in the mounting aperture  200 , is no greater than 0.01″ (0.25 mm), which determines the play between the sash  122  and the frame  120 . In percentage terms, the clearance represents no more than 5.1% of W. The 0.01″ clearance is less than the clearance of 0.03″ (0.75 mm) tolerated in prior art devices. In such devices, the mounting aperture rarely has a minimum diameter less than 0.219″ (5.56 mm) and never less than 0.215″ (5.46 mm), and the prior art clearance of a no. 10 screw is, therefore, 0.03″ (0.69 mm) or 14% of W.  
         [0027]    A comparable tolerance could be achieved by using a no. 11 screw with the typical aperture width of prior art. In this case, W is in the range 0.215-0.219″ (5.46-5.56 mm) and T is 0.200″ (5.08 mm), leading to a clearance in the range 0.015-0.019″ (0.38-0.48 mm) which still a distinct improvement over prior art.  
         [0028]    It is in fact quite unexpected that a low tolerance as disclosed herein should be an advantage, since it would be expected to place more exacting demands on the assembly of the window and to lead to sticking problems in the assembled window. Additionally, the larger tolerance familiar in prior art would be expected to be more consistent with the variety of available weatherproofing seals. On the contrary, it is now shown that the tolerance achieved in the present invention enables one to maximize the degree of weatherproofing while avoiding excessive compression of the weather-stripping between the sash  122  and the frame  120 . Prior art devices with greater tolerance in fact risk on one extreme too much leakage and on the other extreme excessive compression of the weather-stripping which might cause sticking. The present invention avoids either extreme.  
         [0029]    [0029]FIG. 5 illustrates a typical relationship between the sash  122 , the support bracket  10  and the frame  120  in the closed position. The sash has a slotted opening for engaging a weather-strip  124  in an interlocking relationship, so that the weather-strip abuts the frame  120 . The spacing between the frame  120  and the sash  122  is denoted as D in FIG. 5.  
         [0030]    To assemble a window including the present invention, the track is attached to a predetermined position in the frame  120 . Holes are drilled in reproducible positions in the vent, for example with the aid of computer-assisted positioning means such as are currently available for machining devices. No. 10 screws are selected as fasteners, providing that they are accepted by the apertures  200  with sideways clearance of no more than 0.025″ (0.64 mm) and preferably no more than 0.01″ (0.25 mm). The maximum diameter of the aperture allowing an installer to perform a lengthways adjustment, the screws are tightened when the installer is satisfied with the position of the sash  122  in the frame  120 .  
         [0031]    To assemble a window according to the present invention, the track  12  is attached to the frame  120 , with the aid of suitable positioning means. With fasteners  202  selected to be sized appropriately to the mounting apertures  200 , the vent bar  34  is attached to the sash  122 , again with the use of suitable positioning means. Appropriate sizing of the screws  202  requires that they be accepted by the apertures  200  with a minimum (sideways) clearance of no more than 0.02″ (0.51 mm) and preferably no more than 0.01″ (0.25 mm). Note that the minimum clearance is defined as the clearance between the screw  202  and the vent bar  34  across the width of the aperture  200 . The length of the aperture  200 , being aligned with the direction of the vent bar  34 , is of no consequence for the purposes of this invention. The length of the aperture  200  allows an installer to perform a lengthways adjustment, the screws  202  being tightened when the installer is satisfied with the position of the sash  122  relative to the vent bars  34 .  
         [0032]    As indicated earlier, each window will have two support brackets  10 , one on each side. Note that each vent bar  34  has two mounting apertures  200 , one near each end. The preferred clearance of 0.01″ (0.25 mm) applies at each aperture, at which therefore provides a play of ±0.05″ (±0.13 mm). The play between the sash  122  and the frame  120 , while determined by the clearance at the apertures  200 , will usually be greater than ±0.05″ (±0.13 mm). This is illustrated in exaggerated fashion in FIGS. 6A and 6B. FIG. 6A shows the fasteners  202  centered relative to the aperture widths, while FIG. 6B shows the fasteners  202  off-center in opposite directions. Since the vent bar  34  and, specifically, the spacing between the apertures  200  is typically significantly shorter than the corresponding side of the sash  122 , the play at the far end of the sash  122  will be magnified owing to a leverage effect, as is evident from the divergence of the dashed lines of FIG. 6B which represent the alignment of the vent bar  34  and the sash  122 . If, as is typical, the side of the sash  122  is about twice the spacing between the apertures  200 , the play between the far end of the sash  122  and the frame  120  will be ±0.1″ (±0.25 mm) rather than the ±0.05″ (±0.13 mm) at the apertures  200 . This is about one-third of the play in a window supported by a prior art assembly.  
         [0033]    In its preferred embodiment, the reduced tolerance window support bracket assembly includes a four bar hinge. However, it may include other types of hinge.  
         [0034]    While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.