Abstract:
A window assembly, comprises a frame and a sash. The frame has a jamb on at least a first side of the frame. The jamb has an inwardly extending flange. The sash is disposed within the frame. The sash has a stile with an outwardly extending flange along at least one portion of the stile adjacent the jamb. The outwardly extending flange is fixed relative to the sash. The outwardly extending flange is slidably movable adjacent to the inwardly extending flange. The sash has a first position in which the stile is substantially prevented from deflecting by the inwardly extending flange. The sash as a second position in which an end of the outwardly extending flange is positioned beyond an end of the inwardly extending flange, allowing the sash to pivot relative to the frame.

Description:
FIELD OF THE INVENTION 
     The present invention relates to building products generally, and specifically to tilt windows. 
     DESCRIPTION OF THE RELATED ART 
     Tilt windows have become prevalent in residential construction, in large part because of their convenience and attractive appearance. The sash of a tilt window is slidable in the vertical direction during ordinary use. To clean the tilt window, one or more latches at the top of the sash are released, permitting the sash to pivot inward for easy cleaning without completely removing the sash. 
     In the Architectural window class, a window having a test size of at least 1.5 meters× 2.4 meters (5 feet× 8 feet) is required by national standards to be capable of sustaining a load of at least 1900 Newtons per square meter (40 pounds per square foot) with a maximum deflection of any member of the assembly of L/175, where L is the length of the member. 
     In a window sash having a stile on each side, the maximum deflection under a wind load typically occurs at about the midpoint of the stile, where the wind force causes the stile to deflect inward towards the interior of the building. Thus, the deflection of the midpoint of the stile must be maintained below the L/175 limit. 
     To allow use of conventional tilt windows for structures that are required to meet the more stringent standards for commercial and architectural class windows, it is known to fasten (using screws or other removable fasteners) a bracket or brace to the window jamb at a height near the midpoint of the sash. 
     The brace or bracket maintains the maximum deflection below the L/175 limit, but prevents use of the normal tilt feature of the window. To tilt the window inward (e.g., for cleaning), the brace must be removed, typically requiring a tool. Once the brace is removed, there is a likelihood that it will become lost, or that the user will forget to replace the brace, completely defeating the purpose of providing the brace. In addition, the brace or bracket is unsightly. 
     SUMMARY OF THE INVENTION 
     The present invention is a window assembly, comprising a frame and a sash. The frame has a jamb on at least a first side of the frame. The jamb has an inwardly extending flange. A sash is disposed within the frame. The sash has a stile with an outwardly extending flange along at least one portion of the stile adjacent the jamb. The outwardly extending flange is fixed relative to the sash. The outwardly extending flange is slidably movable adjacent to the inwardly extending flange. The sash has a first position in which the stile is substantially prevented from deflecting by the inwardly extending flange. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevation view of an exemplary window assembly according to the invention, as seen from outside of a building in which the window is mounted. 
     FIG. 2 is a cross-sectional view of the window assembly of FIG. 1, taken along section line  2 — 2 . 
     FIG. 3 is an enlarged plan view of the jamb and top stile extrusions shown in FIG.  2 . 
     FIG. 4A is a cross sectional view of the window assembly of FIG. 1, taken along section line  4 A— 4 A. 
     FIG. 4B shows the window of FIG. 4A, with the top and bottom sashes in the tilted position. The sashes appear in the closed position in phantom. 
     FIG. 5 is a simplified isometric sketch showing the sash flange and outwardly extending flange of FIG. 3, when the window is in the closed position. 
     FIG. 6 shows the sash flange and outwardly extending flange of FIG. 5, when the window is in the partially open position for releasing the outwardly extending flange. 
     FIG. 7 is an isometric view of a portion of the jamb shown in FIG.  3 . 
     FIG. 8A is an end view of the jamb extrusion shown in FIG.  3 . 
     FIG. 8B is an end view of a variation of the jamb extrusion shown in FIG.  7 . 
     FIG. 9 is an end view of the outwardly extending flange extrusion shown in FIG.  3 . 
     FIG. 10 is an end view of the top rail extrusion shown in FIG.  4 . 
     FIG. 11 is an end view of the keeper rail extrusion shown in FIG.  4 . 
     FIG. 12 is an end view of the lock rail extrusion shown in FIG.  4 . 
     FIG. 13 is an end view of the bottom rail extrusion shown in FIG.  4 . 
     FIG. 14 is an end view of the top stile extrusion shown in FIG.  3 . 
     FIG. 15 is an end view of the bottom stile extrusion shown in FIG  2 . 
     FIG. 16 is an end view of the sill extrusion shown in FIG.  4 . 
     FIG. 17 is an end view of the head extrusion shown in FIG.  4 . 
    
    
     OVERVIEW 
     FIG. 1 shows a window assembly  100  according to the present invention. The window assembly  100  comprises a frame  101  and at least one sash, such as sashes  102  and  103 . The frame  101  includes two jambs  104 , ahead  106 , and a sill  108 . 
     FIG. 2 is a cross-sectional view of the window assembly of FIG. 1, taken along section line  2 — 2 . FIG. 2 shows the left side of the top sash  102  and the right side of the bottom sash  103 . Although not shown, the right side of the top sash  102  is a mirror image of the left side of the top sash, and the left side of the bottom sash is a mirror image of the right side of the bottom sash. The bottom of FIG. 2 corresponds to the exterior of a building, and the top of FIG. 2 corresponds to the interior of the building. 
     FIG. 3 is an enlarged view of the left end of the top sash  102 . The jamb  104  has an elongate flange  104   a . A stop means, such as stop  130  is attachable to the jamb  104 . The stop  130  has a flange  130   a  that projects inwardly (towards the center of the sash  102 ) when the stop  130  is attached to the jamb  104 . 
     The sash  102  has a stile  140 . Stile  140  has an outwardly extending flange  141  along at least one portion of the stile of the sash adjacent the jamb  104 . The outwardly extending flange  141  extends outward (away from the center of the sash  102 , towards the jamb  104 ). The outwardly extending flange  141  is slidably movable between the elongate flange  104   a  of the jamb  104  and the flange  130   a  of the stop, as the sash is raised or lowered 
     FIG. 2 also shows the bottom sash  103 . The bottom sash  103  has a stile  150 . Stile  150  has an outwardly extending flange  151  along at least one portion of the side of the sash adjacent the jamb  104 . The outwardly extending flange  151  extends outward (away from the center of the sash  103 , towards the jamb  104 ). The jamb  104  has a second stop  130  for the bottom sash  103 . The outwardly extending flange  151  is slidably movable between the flange  104   b  of jamb  104  and the flange  130   a  of the stop, as the sash  103  is raised or lowered. 
     FIG. 5 is a simplified isometric sketch showing the outwardly extending flange (flange  151 ) of bottom sash  103  and the stop  130 , when the sash  103  is in the closed position. The jamb  104  is omitted from FIG. 5 for ease of viewing the outwardly extending flange  151  and stop  130 . Only the stop  130  is shown, at an approximate height in which the stop would be located on the jamb  104 . If the jamb were shown with the sash  103  installed in the jamb  104 , the stop and the flange of the frame would be hidden when the sash is in this position (See, for example, FIG.  1 ). 
     FIG. 7 is an isometric view of a portion of the jamb  104 , showing the positioning of the stop. As shown in FIG. 7, the length “L” represents the height of the sash  103 . The stop  130  is positioned at approximately the midpoint of the height of the sash  103 . 
     Referring again to FIG. 5, the outwardly extending flange  151  of the sash  103  may have a first outwardly extending flange portion  151   a  and a second outwardly extending flange portion  151   c  separated by a space or cutout  151   b . The first outwardly extending flange portion  151   a  extends to approximately the top end of the sash  103 , and the second outwardly extending flange portion  151   c  extends to approximately the bottom end of the sash opposite the first end of the sash. The space or cutout  151   b  may, for example, be located at a distance from the bottom of the sash of approximately one third of the height of the sash, or other suitable locations may be used. The space or cutout  151   b  is at least as long as the flange  130   a  of the stop  130 . 
     The space or cutout  151   b  may be alternatively located at a position different from one third of the height of the sash  103 . If the cutout is located closer to the bottom of the sash  103 , then the sash must be raised by a distance greater than one sixth of the sash height to align the cutout with the stop for pivoting the sash inward. The cutout  151   b  should be positioned far enough from the midpoint of the sash  103  so that the sash  102  clears the sill  108  when the cutout is aligned with the stop  130 . 
     The lower portion  151   c  is not required to perform any function. It may, however, be easier to form flange  151  along the complete length of the sash  103 , and form a cutout  151   b  therein, than to form the flange along only a portion of the sash. Alternatively, the cutout  151   b  may extend to the bottom of the sash, so that there is only one portion  151   a  of the flange present. 
     The stop  130  is located at a height approximately equal to one half of the height of the sash  103 . When the sash  103  is in the closed position shown in FIG. 5, the stile of the sash is prevented from deflecting by the flange  151  of the frame and the flange  130   a  of the stop  130 . (The sash is also prevented from pivoting inward.) The stop  130  may be about 7.5 centimeters (3 inches) high. Other lengths may be used, so long as the stop is of sufficient strength and stiffness to limit deflection of the stiles  140  and  150  to a desired level. 
     Although an elevation view of the outwardly extending flange  141  of the top sash  102  is not included herein, flange  141  is similar to flange  151 , and the positioning of stop  130  in the slot  117  for the upper sash  102  is similar to that shown and described above with respect to the lower sash  103 . That is, the stop  130  in slot  117  is at a height approximately corresponding to the midpoint of top sash  102  in the position of FIG. 4A, and the cutout of flange  141  is at a distance of about one third the height of the top sash  102  (the distance being measured from the top of the top sash.) Thus, the top sash  102  is lowered by a distance of about one sixth of the height of the sash to reach the pivoting position. The location of the cutout in flange  141  may also be varied to provide a different pivoting position for the top sash, in the manner described above with respect to the bottom sash. 
     FIG. 6 shows the sash  103  and outwardly extending flange  151  of FIG. 5, when the sash  103  is in the partially open position for releasing the outwardly extending flange  151 . The sash is slidably raised to a height of about one sixth of the height of the sash. At this height, the cutout  151   b  of outwardly extending flange  151  lines up with the stop  130  of the sash  103 . In this position, the bottom end of the outwardly extending flange portion  151   a  is positioned beyond the top of stop  130 , allowing the sash  103  to pivot relative to the frame  101 . 
     The structure described above provides great strength in a tiltable window, sufficient to withstand high wind loads with minimal deflection. In particular, if a stop  130  is provided on each side of the sash  103 , then the flange  130   a  of each respective stop  130  provides a bearing surface that is sufficiently strong and stiff to resist at least one half of the maximum expected wind pressure force applied against the sash  103 , and transmitted via the outwardly extending flange  151  of the sash to the stop. Then the two stops  130  together can withstand the maximum combined load. 
     Further details of the exemplary embodiment are described below. 
     DETAILED DESCRIPTION 
     FIGS. 2,  3 , and  8 A show an end view of an extrusion for a window jamb  104  suitable for use in accordance with the invention. A single jamb extrusion  104  may be used for both the right and left sides of the window frame  101 . The right jamb  104  is a mirror image of the left jamb  104 , and is obtained by merely flipping the extrusion by 180 degrees. (The same is true for the stop  130 , the top stile  140  and the bottom stile  150 .) 
     The jamb  104  has two slots  115  and  117  for receiving respective stops  130 . The slots  115  and  117  may be identically shaped, if the stops  130  are identically shaped. Alternatively, each slot may have a different cross section, if the stops for the upper and lower sashes are shaped differently from each other (not shown). The descriptions of slots  115  and  117 , below, are identical to each other. 
     In the example, the slot  115  ( 117 ) is asymmetrical. The slot  115  ( 117 ) has a rectangular portion  115   a  ( 117   a ) and a wedge shaped portion  115   b  ( 117   b ). By using a different cross section shape for each end of the slot  115  ( 117 ), correct orientation of the (non-symmetrical) stop  130  is assured. FIG. 9 shows the exemplary stop  130 . Stop  130  has a heel-shaped portion  131   a  that fits into slot portion  115   a  ( 117   a ), and a foot shaped portion  131   b  that fits into slot portion  115   b  ( 117   b ). 
     Alternative cross sections may be used for the stop  130 . The heel  131   a  and foot  131   b  are not required shapes; these shapes are used in the exemplary embodiment to conform to the shape of slot  115 . Any complementary shapes may be used for slot  115  and stop  130 . Also, the design of the slot and the stop may be varied so that the stop is symmetrical. 
     The exemplary stop means  130  is a separate component mounted in position in slot  115  ( 117 ) by, for example, crimping welding, soldering, or by use of an adhesive. In an alternative variation (not shown), the stop means may be formed integrally as a part of the same extrusion as the jamb. Since the extrusion would have a constant cross section from top to bottom, the stop would extend from the top to the bottom immediately after extrusion. The top and bottom portions of the stop flange would then be cut off using a conventional cutting tool, so that a short stop flange having the desired length would remain, positioned at a height approximately adjacent to the center of the sash. 
     With the stop  130  installed, the combination of the elongated flange  104   a  and the stop flange  130   a  form a channel for slidably receiving the outwardly extending flange  141  of the top stile  140 . The elongated flange  104   a  prevents the sash  102  from pivoting outward. The stop flange  130   a  substantially prevents the stile  140  of sash  102  from deflecting or bowing inward. In particular, stop flange  130   a  substantially prevents deflection under wind loading. In the exemplary embodiment, the stop flange  130   a  prevents the stile  140  from deflecting by more than L/175 at the center of stile  140 . The stop flange  130   a  also prevents the sash  102  from pivoting inward, unless the sash  102  is specifically placed at the pivoting height L/6 shown in FIG.  6 . 
     Similarly, for the bottom sash, the combination of the elongated flange  104   b  and the stop flange  130   a  form a channel for slidably receiving the outwardly extending flange  151  of the bottom stile  150 . The elongated flange  104   b  prevents the sash  103  from pivoting outward. The stop flange  130   a  substantially prevents the stile  150  of sash  103  from deflecting. 
     As best seen in FIGS. 2 and 3, when the sash is in its closed position with the outwardly extending flange  141  (or  151 ) slidably received between stop flange  130   a  and elongated flange  104   a  (or  104   b ), the stop  130  and the outwardly extending flange  141  (or  151 ) are completely concealed from view by an observer on the interior of the building. 
     Other aspects of the window assembly shown in the exemplary embodiments are now described. 
     FIGS. 3 and 8A show the jamb  104 . The jamb  104  has a channel  109  for the balance shoe  112   a  of the top sash and a channel  119  for the balance shoe  112   b  of the bottom sash. A balance shoe is a conventional mechanism that allows the sash to be slidably raised and lowered between the right and left jambs (FIG.  4 A), or pivotally tilted inward for cleaning (FIG.  4 B). In a typical configuration, the sash  102  has a non-circular pin  129  (FIGS. 4A and 4B) projecting outwardly on each side at the bottom of the sash. The balance shoes  112   a  and  112   b  have cams (not shown) that receive the pins of the sash. When the sash  102  is raised or lowered, the balance shoe and cam move up and down correspondingly, within the respective channels  109  and  119 . When the sash  102  is pivoted inward (as shown in FIG.  4 B), the cam (not shown) rotates, but is locked from being raised or lowered until the sash is returned to its normal position (FIG.  4 A). 
     The top sash  102  and bottom sash  103  may each have conventional spring loaded pins or latches (not shown) that are biased to project outwardly into the balance shoe channels, when the sashes are in the positions shown in FIG.  4 A. In the exemplary embodiment, the stop  130  and outwardly extending flange  141  (or  151 ) prevent the window from pivoting inward unless the stop  130  is aligned with the cutout  151   b  of the lower sash (not shown for the upper sash). The spring loaded pins or latches prevent the sash  102  (or  103 ) from inadvertently pivoting inwardly when the sash is moved past the pivot position (i.e., when the lower sash is raised one sixth of its height, or the upper sash is lowered by one sixth of its height). 
     To pivot the sash  102  or  103  inward (e.g., for cleaning), the bottom sash  103  is raised (or top sash  102  is lowered) by about one sixth of its height, and the spring loaded pins or latches are manually pressed inward, to release the top of the sash  103  (or  102 ) from the jamb  104 . To make it easier to align the sash  102  or  103  at the height for pivoting, indicia may be placed on the jamb  104  and/or the stile  150 . Any indicia may be used, including printed matter. A dimple may be a preferred form of indicia, because a dimple is unobtrusive and cannot be inadvertently peeled or rubbed off. 
     In addition to the features described above, jamb  104  has a screen track  111  for receiving a conventional screen. Jamb  104  may also have a lightweight material  113  added in channel  118  to strengthen the jamb. This material may be, for example, a conventional two-part polyurethane resin or equivalent material. Two screw receiving ports  114  and  116  receive screws  114   a  and  116   a  (FIGS. 4A and 4B) that are used to fasten the head  106  and sill  108  to the jambs  104 . 
     The panes  121  and  122  are mounted with a spacer  132  therebetween. The spacer may, for example, be formed of aluminum, and filled with a desiccant  134 . The spacer is generally formed in a rectangle, at the top, bottom, left and right sides of the sash  102 . When the panes  121  and  122  are mounted on the spacer  132 , and a sealant  133  is applied. The sealant may, for example be a silicone based adhesive or the like. 
     FIG. 8B shows a mulling jamb  104 ′ that may be used to install two of the exemplary windows side-by-side. In a side-by-side configuration (not shown), the two outer jambs and one of the two inner jambs are of the type shown in FIG.  8 A. The remaining inner jamb is a mulling jamb  104 ′ of FIG.  8 B. The mulling jamb has two projections  137  and  138  that fit inside of the respective walls  135  and  136  in the neighboring jamb  104 . The gaps between the walls  135  and  136  and the projections  137  and  138  are then filled with a pliable sealant (e.g., silicone or acrylic). Other features of mulling jamb  104 ′ are identical to those in jamb  104 , as described above. 
     FIGS. 14 and 15 show the top stile  140  and bottom stile  150 , respectively. An exemplary stile  140  is best seen in situ in FIG.  3 . The top stile  140  has an outwardly extending flange  141 , and the bottom stile  150  has an outwardly extending flange  151 . The operation of these flanges is described above. The stiles  141  and  151  retain the window panes  121 - 124  in place. The panes  121 ,  122  are retained between the glazing leg  142  and a spline  161  (FIG.  3 ). The spline  161  is in turn held in place by a glazing bead  160  (FIG.  3 ). The glazing bead  160  is secured in a channel  148  by its engagement with retaining wall  147  of stile  140 . Similarly, the panes  123 ,  124  are retained between the glazing leg  152  and a spline  161  (FIG.  2 ). The spline  161  is in turn held in place by a glazing bead  160  (FIG.  2 ). The glazing bead  160  is secured in a channel  158  by its engagement with retaining wall  157  of stile  150 . 
     As best seen in FIG. 14, stile  140  has two channels  149  for receiving weather stripping  143  (FIG.  3 ). A channel  146  receives a lightweight material  144  such as a two part polyurethane or the like. Screws  145  or similar fasteners are used to attach the stile to the top rail  125  (FIG. 10) and the keeper rail  126  (FIG.  11 ). 
     FIGS. 4A and 10 show the top rail  125  of the top sash  102 . Top rail  125  has a glazing leg  164 . Panes  121  and  122  are retained in place between glazing leg  164  and a spline  161  (FIG.  4 A). The spline  161  is held in place by a glazing bead  160  secured in the channel  168 , and engaging retaining wall  167 . A channel  165  is filled with a rigid, lightweight material  164  such as a two part polyurthane (FIG.  4 A). A channel  166  retains weather stripping material  143 . Two screw ports  169  receive the fasteners that attach the top stiles  140  to the top rail  125 . A latch port  170  receives a latch  171  (FIG. 4A) that locks the top sash in the closed position. 
     FIGS. 4A and 11 show the keeper rail  126  of the top sash  102 . Keeper rail  126  has a glazing leg  172 . Panes  121  and  122  are retained in place between glazing leg  172  and a spline  161  (FIG.  4 A). The spline  161  is held in place by a glazing bead  160  secured in the channel  178 , and engaging retaining wall  177 . A channel  175  is filled with a rigid, lightweight material  174  such as a two part polyurethane (FIG.  4 A). Two screw ports  179  receive the fasteners that attach the top stiles  140  to the bottom rail  126 . A mounting surface  171  holds the catch (not shown) of the window lock  190 . A channel  176  retains weather stripping material  143 . An upwardly projecting flange  173  receives a mating flange  183  of the lock rail  127  to secure the top and bottom sashes in a weather-tight relationship when both sashes are closed (as shown in FIG.  4 A). A latch port  196  receives a latch  191  that secures the lower sash in the closed position. A channel  180  holds the outwardly projecting members  129 , about which the top sash  102  pivots for cleaning. 
     FIGS. 4A and 12 show the lock rail  127  of the bottom sash  103 . Lock rail  127  has a glazing leg  182 . Panes  123  and  124  are retained in place between glazing leg  182  and a spline  161  (FIG.  4 A). The spline  161  is held in place by a glazing bead  160  secured in the channel  188 , and engaging retaining wall  187 . A channel  185  is filled with a rigid, lightweight material  184  such as a two part polyurethane (FIG.  4 A). Two screw ports  189  receive the fasteners that attach the bottom stiles  150  to the lock rail  127 . A mounting surface  181  holds the window lock  190 . Two spring-biased latches (not shown) are also mounted on the ends of mounting surface  181 , for preventing the sash  103  from pivoting inward, except when pivoting is desired for cleaning. A channel  186  retains weather stripping material  143 . An downwardly projecting flange  183  is received by a mating flange  173  of the keeper rail  126  to secure the top and bottom sashes in a weather-tight relationship when both sashes are closed (as shown in FIG.  4 A). 
     FIGS. 4A and 13 show the bottom rail  128  of the bottom sash  103 . Bottom rail  128  has a glazing leg  192 . Panes  123  and  124  are retained in place between glazing leg  192  and a spline  161  (FIG.  4 A). The spline  161  is held in place by a glazing bead  160  secured in the channel  198 , and engaging retaining wall  197 . A channel  195  is filled with a rigid, lightweight material  194  such as a two part polyurethane (FIG.  4 A). Two screw ports  199  receive the fasteners that attach the bottom stiles  150  to the bottom rail  128 . A channel  193  holds the outwardly projecting members  129 , about which the lower sash pivots for cleaning. A latch port  196  receives a latch  191  that secures the lower sash in the closed position. 
     FIG. 16 shows the sill extrusion  108 . The sill  108  has two channels  206  for receiving weather stripping  143 . A channel  205  is filled with a rigid, lightweight material  204  such as a two part polyurethane (FIG.  4 A). A tooth  201  is engageable by the latch  191  of the bottom rail  128 , to secure the lower sash  103  in the closed position. 
     FIG. 17 shows the head extrusion  106 . The head  106  has a channel  216  for receiving weather stripping  143 . A channel  215  is filled with a rigid, lightweight material  214  such as a two part polyurethane (FIG.  4 A). A tooth  211  is engageable by the latch  171  of the top rail  125 , to secure the top sash  102  in the closed position. 
     Windows fabricated according to the exemplary embodiment of the present invention achieve the convenience of conventional tilt windows with enhanced resistance to deflection. For example, the window assembly may be an Architectural class window having a test size of at least 1.5 meters×2.4 meters (5 feet×8 feet), and the window is capable of sustaining a load of at least 1900 Newtons per square meter (40 pounds per square foot) with a maximum deflection of any member of the assembly of L/175, where L is the length of the member. 
     Further, the exemplary embodiment does not require the removal and re-mounting of a separate deflection reducing brace every time the window is to be tilted in for cleaning. In the exemplary embodiment, when the sash is installed in the frame, the anti-deformation feature is deployed without requiring any separate steps by the user. Because the stop means is integrally attached to (i.e., secured to, or part of) the jamb, the stop means cannot become lost or separated from the window. The exemplary window can also be tilted in for cleaning in fewer steps and in less time than prior art windows that have a separate brace. 
     Although the invention has been described in terms of exemplary embodiments, it is not limited thereto. Rather, the appended claim should be construed broadly, to include other variants and embodiments of the invention which may be made by those skilled in the art without departing from the scope and range of equivalents of the invention.