Patent Publication Number: US-9845626-B2

Title: Removable window sash system with integrated spring biased retainer

Description:
RELATED APPLICATIONS 
     This application claims the benefit of provisional patent application No. 62/120,866 filed Feb. 25, 2015. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     In general, the present invention relates to windows that have sashes that are designed to be easily removed from a window frame. More particularly, the present invention relates to the structure of spacers that are used to prevent a window sash from cocking within a window frame as it is opened and closed. 
     2. Prior Art Description 
     There are many types of windows used in modern construction. Some windows are designed to open, some are not. Of the windows that are designed to open, some windows have sashes that open vertically and others have sashes that slide open laterally, or rotate outwardly. 
     Windows that have vertically opening sashes are the most common window used in residential home construction. Vertically opening windows are either single-hung, having one sash that opens, or double-hung, having two sashes that open. In both single-hung and double-hung windows, a counterbalance system is used to hold a window sash up once it is opened. If no counterbalance system is used, gravity causes the sash of the window to close as soon as it is opened and released. 
     Counterbalance systems for single-hung and double-hung windows typically use coil springs to counterbalance the weight of the window sashes. The presence of a counterbalance system requires that a substantial space be left between the sash of the window and the jambs of the window frame. The counterbalance system operates in this space. The counterbalance system is protected from view and from contact by using extruded window frame jambs that are generally U-shaped in cross section. The counterbalance system sits within the center of the groove defined by this track and is thus protected from sight. 
     When a window is manufactured, the sashes of the window are made separately from the frame of the window. The sashes are later assembled into the frame. Due to variations in manufacturing tolerances, the width of a window sash may vary by up to ⅛ th  of an inch. Likewise, the distance between jambs in a window frame may also vary by up to ⅛ th  of an inch. As a consequence, if an undersized sash is assembled into an oversized window frame, there may be over ¼ inch of play between the sash and the tracks of the window frame. 
     If a window sash has too much play in a window frame, the window sash may cock in position when moved by a person or when influenced by the counterbalance system. Additionally, if the window sash cocks in position, a gap may be created between the window and the sill, thereby greatly reducing the insulation rating for that window. 
     In the prior art, window sashes have been provided with spacers. However, many of the prior art spacers have drawbacks. Many spacer systems require that slots and/or grooves be milled into the structure of the window sash in order to accommodate the spacer. This adds significantly to the cost and manufacturing complexities of the window sash. Such prior art spacers are exemplified by U.S. Patent Application Publication No. 2005/0144845 to Heck et al. Other spacer systems can be retroactively added to existing window sashes, however, the spacers are visible and detract from the clean aesthetics of a flat window sash. Such prior art spacers are exemplified by U.S. Pat. No. 8,424,245 to Kunz et al. 
     A need therefore exists for a spacer system that can be added in a window assembly, both at its time of manufacture and retroactively, that does not require changes in the window sash and does not detract from the aesthetics of the window sash. This need is met by the present invention as described and claimed below. 
     SUMMARY OF THE INVENTION 
     The present invention is a spacer that attaches to a window sash in order to create an improved window construction. The window construction includes a window frame that has side tracks. A window sash is set within the side tracks of the window frame, wherein the window sash can move to open and close within the side tracks. In order to provide the window sash the freedom it needs to move, gap spaces exists between the window sash and the side tracks. 
     The presence of the gap spaces enable the sash to move laterally as it opens and closes. This can cause the window sash to cock and bind. To prevent cocking, spacers are provided. The spacers attach to the sides of the window sash inside the tracks where the spacers are not visible. 
     Each spacer has a base, a spring arm that extends from the base, and a contact head that is supported by the spring arm. The base is mounted to the window sash within a gap space. The spring arm extends into the gap space and biases the contact head against the side track. The contact head also overlaps a segment of the window sash, therein presenting a physical barrier that greatly reduces the degree of lateral movement achievable by the widow sash. The reduced degree of possible lateral movement inhibits the window sash from cocking within the window frame. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the present invention, reference is made to the following description of exemplary embodiments thereof, considered in conjunction with the accompanying drawings, in which: 
         FIG. 1  shows a window sash in a window frame containing the present invention system; 
         FIG. 2  shows an enlarged view of the section of  FIG. 1  contained in circle  2 ; 
         FIG. 3  shows a perspective view of the spacer and illustrates its placement on the window sash; 
         FIG. 4  shows an enlarged perspective view of the spacer and illustrates its attachment orientation in relation to the window sash; 
         FIG. 5  shows a fragmented top view of the exemplary system of  FIG. 1 , viewed along section line  5 - 5 ; and 
         FIG. 6  shows an enlarged perspective view of the spacer and illustrates its attachment orientation in relation to the window sash as external deformation forces are applied; 
         FIG. 7  is the same view perspective as  FIG. 5  as external deformation forces are applied; and 
         FIG. 8  shows an alternate embodiment of the spacer. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Although the present invention system and method can be embodied in many ways, only two embodiments have been selected for the purposes of illustration and discussion. The illustrated embodiments, however, are merely exemplary and should not be considered limitations when interpreting the scope of the appended claims. 
     Referring to  FIG. 1  in conjunction with  FIG. 2 ,  FIG. 3 ,  FIG. 4 , and  FIG. 5 , a window assembly  10  is shown. The window assembly  10  has a window frame  12  that holds a window sash  14 . The window sash  14  typically slides in tracks  16  that are formed into the sides of the window frame  12 . This enables the window sash  14  to move up and down within the window frame  12 . 
     The window sash  14  is comprised of a pane of glass  18  that is surrounded by framing elements. The framing elements include two vertical side elements  20  that are disposed on the opposite vertical sides of the pane of glass  18 . The two vertical side elements  20  are parallel and extend in a vertical plane when the window sash  14  is seated vertically within the window frame  12 . 
     A groove  21  is formed along the length of both of the vertical side elements  20 . Each groove  21  is defined by two side walls  23 . Each of the side walls  23  has wall edge  25  that faces the adjacent window frame  12 . 
     Two spring biased spacers  22  are provided that attach to the vertical side elements  20  of the window sash  14  within the grooves  21 . Each of the spring biased spacers  22  has a complex shape. Each spring mounted spacer  22  has a mounting base  24 . A hole  26  is formed through the mounting base  24  that enables the mounting base  24  to be attached directly to the vertical side elements  20  of the window frame with a screw  28  or similar mechanical fastener. 
     A contoured spring arm  32  extends from the mounting base  24 . The contoured spring arm  32  curves away from the vertical side element  20  of the window sash  14 , as it extends away from the mounting base  24 . The spring arm  32  terminates with a contact head  34 . The contact head  34  is slightly offset from the spring arm  32 . This creates a ledge  33  at the rear of the contact head  34 . Due to the shape of the contoured spring arm  32 , the contact head  34  is biased to a position where the ledge  33  behind the contact head  34  is positioned atop the wall edge  25  of the side wall  23  that faces the adjacent window frame  12 . Accordingly, if a force is applied to the contact head  34  in the direction of arrow  37 , the ledge  33  of the contact head  34  will press against the wall edge  25  and the contact head  34  will not move. 
     It will therefore be understood that the presence of the contact head  34  over the wall edge  25  of the window sash  14  has the affect of widening the window sash  14 . As such, the movement of the window sash  14  in the direction of arrow  35  is reduced. As a consequence, the degree in which the window sash  14  is free to cock is significantly decreased. 
     The contact head  34  is spring biased into its extended position atop the wall edge  25 . To remove the window sash  14  from the window frame  12 , the contact head  34  must be retracted into the groove  21  on the window sash  14 . The contact head  34  is supported by the contoured spring arm  32 . The contoured spring arm  32  can be made of spring steel or a resilient molded plastic. As such, the contoured spring arm  32  is both flexible and resilient. Therefore, it will be understood that as the contact head  34  can be moved by deforming the contoured spring arm  32 . 
     Since the spring biased spacer  22  is connected to the vertical side element  20  of the window sash  14 , the spring biased spacer  22  moves with the window sash  14  within the window frame  12 . A top stop projection  36  extends from the contact head  34  of the spring biased spacer  22 . Likewise, a bottom stop projection  38  extends from the mounting base  24  of the spring biased spacer  22 . The top stop projection  36  enables a person to engage and move the contact head  34  with a tool, such as a screwdriver, without damaging the contact head  34 . The bottom stop projection  38  helps stabilize and align the mounting base  24  so that it does not rotate out of place. 
     When affected only by the bias of the contoured spring arms  32 , the contact heads  34  are positioned over a wall edge  25  on the window sash  14 . Furthermore, the contact heads  34  are biased against the opposing walls  39  in the tracks  16  of the window frame  12 . When the window sash  14  is moving up and down in the window tracks  16 , the spring bias behind the contact heads  34  remains. However, the spring biased spacers  22  do not prevent the sash  14  from moving straight up and straight down. 
     It will be understood that to remove a sash  14  from the window frame  12 , the contact head  34  on at least one of the spring biased spacers  22  must be deformed against its spring bias back into the groove  21  of the window sash  14 . Referring to both  FIG. 6  and  FIG. 7 , it will be understood that a person can reach a finger or tool into the track  16  from atop the window sash  14  and apply forces in the direction of arrow  37  and arrow  41 . The external forces are applied to the top stop projection  36  to prevent any contact damage to the contact head  34 . As a force is applied in the direction of arrow  41 , the contact head  34  is moved laterally out of contact with the wall edge  25 . As the force is applied in the direction of arrow  37 , the contoured spring arm  32  further deforms and the contact head  34  retracts into the groove  21  of the window sash  14 . Once retracted, the window sash  14  can move laterally in the direction of arrow  35 , while in the track  16  of the window frame  12 . This lateral movement can be advanced to a point where the sash  14  disengages from the window track  16 . The sash  14 , once free of the track  16 , can be removed from the window frame  12 . 
     Since the spring biased spacers  22  are positioned in the guide track  16 , the spring biased spacers  22  cannot be observed by a person who raises or lowers the window sash  14 . Furthermore, the spring biased spacers  22  attach to the window sash  14  with a simple screw. As such, the spring biased spacers  22  can be easily added to most every window sash model and style without any alteration of the window sash. 
     In the embodiment illustrated in  FIGS. 1 through 7 , the spring biased spacers  22  have a contoured spring arm  32  that is generally shaped as an inverted letter S. This shape is arbitrary. Many other shapes can be used to provide the needed spring movement to the contact head supported by the contoured spring arm. Such an alternate embodiment is shown in  FIG. 8 . Referring to  FIG. 8 , it can be seen that the contoured spring arm  32   a  can have any shape that both biases the contact head  34   a  outwardly and enables the contact head  34   a  to be deformed inwardly. In the shown alternate embodiment, the spring arm  32   a  has the shape of an inverted letter U. However, the contact head  34   a  is still biased outwardly and performs the same functions as were previously described. 
     It will be understood that the embodiments of the present invention that are illustrated and described are merely exemplary and that a person skilled in the art can make many variations to those embodiments. All such embodiments are intended to be included within the scope of the present invention as defined by the appended claims.