Patent Publication Number: US-6338222-B1

Title: Universal sash tether clasp and anchoring apparatus for window counterbalancing system

Description:
BACKGROUND OF THE INVENTION 
     The present invention is related generally to the art of counterbalancing systems for conventional double-hung or vertical sliding windows and the like, and more specifically to sash tethering devices which are externally mountable for universal use in connection with such counterbalancing systems. 
     In conventional indoor double-hung or vertical sliding windows systems, use of counterbalancing systems to ease the load of lifting the lower window sash is commonplace. Such counterbalancing systems are most commonly designed to be mounted within the window jambs such that they are substantially, if not completely, hidden from view. For this reason, conventional double-hung windows and the counterbalancing systems there for are generally custom designed and not universally interchangeable with other window brands. 
     While indoor double-hung windows are most commonly custom built for use with a particular counterbalancing system, outer storm windows of the double-hung type have conventionally been devoid of counterbalancing systems altogether. The reason for this is that outer storm windows are generally of light construction, not requiring any need to offset the load of the lower sash window. However, in recent times, storm windows have been built of a much more solid and heavier construction to help cut down outdoor noise levels. While conventional storm windows are generally constructed with windowpanes of {fraction (3/32)} inch thickness (SSB) or ⅛ inch thickness (DSB), newer storm windows are oftentimes constructed with {fraction (3/16)} inch thickness windowpanes, or with ¼ inch laminated glass. This is particularly the case in homes near airports and the like, where noise levels are significantly increased. Storm windows used in such areas are now commonly constructed with increased strength and insulative capacity, and consequently with increased weight. 
     As storm windows of this type are not commonly designed to be fitted with counterbalancing systems, particularly with those that are built into the window jambs and hidden from view, there is a distinct need for a counterbalance system which can be mounted to the exterior of such a window for universal application to any type or brand thereof. Such a universal system may be used to modify or repair existing double-hung windows, as well as be incorporated into new windows. It is with this object in mind that we have developed our improved counterbalance sash tether clasp and anchoring system as described and shown hereinafter. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with the present invention, we have conceived of an improved universally mountable sash tether clasp and anchoring device which provides for convenient accessibility and versatility in the installation and use of new or pre-existing double-hung windows. The sash tether clasp is externally mounted to the lower sash of the window, and includes an improved means for engaging the sash tethering device of the counterbalance system in readily releasable locking engagement. 
     The tether clasp includes a base portion which is externally mountable upon the lower window sash, and a generally U-shaped catch member and separate locking member which extend outwardly therefrom. The catch member is cantilevered at one end to the base portion and terminates at its other end in a pair of transversely spaced opposed leg members, which are defined by an open channel extending therebetween. 
     The locking member is disposed below the catch member and is spaced slightly therefrom. The locking member is also cantilevered at one end to the base portion and is free at its opposite end. The intermediate portion of the locking member is curved such that the extrados surface of the arcuate portion faces upwardly toward the catch member. The transverse dimensions of the locking member are less than that of the catch member, and the locking member is generally centrally disposed relative to the catch member, such that the arcuate portion thereof extends upwardly toward the channel extending between the opposite legs of the catch member. 
     The tethering device which connects to the tether clasp includes a typical balance cord which terminates at its free end with a generally bell-shaped anchor member. The anchor member has outer walls which diverge outwardly from its upper end toward the lower bell mouth portion thereof. The anchor member is constructed such that at least the lower bell mouth portion of the anchor member is hollow, so as to form an inwardly protruding recess in the lower end thereof. 
     In operation, the generally bell-shaped anchor member of the tethering device may be connected in releasable locking relation with the tether clasp by inserting the anchor member between the catch member and locking member of the tether clasp. The diverging outer wall portions of the anchor member  21  are constructed such that they may be received within the channel portion between the opposing legs of the catch member. Upon insertion of the anchor member in such manner, the lower bell mouth portion of the anchor will engage the arcuate portion of the locking member and cause the same to deflect slightly downward to allow the anchor member to move past the arc and seat against the catch member. 
     Once the anchor member is seated between the opposing legs of the catch member, the spring bias of the locking member will cause the same to return to its natural resting place, wherein at least the extrados surface of the arcuate portion of the locking member will extend within the lower recess portion of the bell mouth of the anchor member. By so doing, the locking member effectively holds the anchor member of the tethering device in releasable locking engagement with the catch member of the tether clasp, which is connected to the lower sash of the window. Because the counterbalance system exerts an upward biasing force on the tethering device, the outer diverging wall portions of the anchor member engage the opposing legs of the catch member, thereby effectively reducing the load of the lower window sash when opening the same. 
     Through the use of our universal tether clasp and anchoring system for double-hung windows, an external counterbalancing system may be used to provide versatility with respect to both installation and use on new or pre-existing windows. The improved accessibility and readily releasable locking engagement of the tether clasp and anchor system effectively enhances the performance and ease of operation of the double-hung window upon which it is installed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects and advantages of the invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views, and in which: 
     FIG. 1 is a vertical cross-sectional view of a double-hung storm window seated within a window opening and incorporating our invention, the cross-section lines of the window frame having been omitted to facilitate clarity of the drawing and discussion of same; 
     FIG. 2 is a perspective view of a sash tether clasp embodying the principles of our invention which mounts to the lower sash of a double-hung window; 
     FIG. 3 is a side elevational view of the sash tether clasp shown in FIG. 2; 
     FIG. 4 is a top plan view of the sash tether clasp shown in FIG. 2; 
     FIG. 5 is a partial perspective view of the terminal end of a balance tethering device showing the anchor member which embodies the principles of our invention, the lower portion of the anchor member being broken away to show the hollow interior thereof; and 
     FIG. 6 is a partial side elevational view of the anchor member in FIG. 5 shown in releasable locking engagement with the sash tether clasp shown in FIGS. 2-4, in accordance with our invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     For purposes of illustration, shown in FIG. 1 of the attached drawings is a conventional double-hung storm window  1  to which our invention has been applied. Storm window  1  is disposed between the overhead window molding  2  and the lower window sill (not shown) in a conventional manner. The outer frame  3  of storm window  1  is appropriately secured within the window opening by conventional means, such as screw  4  which secures frame  3  to the window head  5 . 
     Storm window  1  includes an upper sash  6  carrying an upper window pane  7 , and a lower sash  8  carrying a lower window pane  9 . As shown in FIG. 1, when sash  8  is lowered into its closed position, its upper frame section  10  preferably interengages with the lower frame section  11  of upper sash  6 . In such position, flange  12  of upper frame section  10  and flange  13  of lower frame section  11  interlock to form a tight joint between the upper and lower sashes of storm window  1 . 
     As further shown in FIG. 1, a conventional counterbalancing system  14  including balance mechanism  15  is externally mounted to window  1  adjacent the upper end thereof. Balance mechanism  15  is carried within housing  16  which is secured to the upper frame  17  of the storm window&#39;s upper sash  6  by a plurality of conventional screws  18 . Extending from the balance mechanism  15  to the lower sash  8  of window  1  is a sash tethering device  19  which is spring biased upwardly by balance mechanism  15 . 
     Tethering device  19  is comprised of a balance cord  20  which terminates at its lower end with an anchor member  21 . Tethering device  19  is movable between a releasable locking position wherein anchor member  21  engages tether clasp  22  mounted externally on lower sash  8 , and a free position (shown in phantom) wherein anchor member  21  is free from engagement with tether clasp  22 . 
     As shown best in FIG. 2, tether clasp  22  includes a base portion  23  which includes openings  24  and  25  through which conventional screws  26  are inserted to externally mount the same to the outer frame  27  of lower sash  8 . Clasp  22  includes a catch member  28  and a locking member  29  which extend outwardly from base portion  23  in a plane generally perpendicular thereto. Catch member  28  and locking member  29  are vertically spaced from one another, whereby the locking member  29  is disposed below catch member  28  and extends outwardly from base portion  23  in a plane generally parallel with catch member  28 . Catch member  28  and locking member  29  function to retain anchor member  21  in releasable locking interengagement therebetween, as shown in FIGS. 1 and 6, and described in more detail hereafter. 
     As shown best in FIGS. 2 and 4, catch member  28  is cantilevered at one end  30  to base portion  23 , the opposite end  31  of which terminates in a pair of transversely spaced opposed leg members  32  and  33 . Disposed between leg members  32  and  33  and forming the same is a cutaway channel portion  34  which leads into the centerly disposed substantially circular cutout portion  35  in catch member  28 . Legs  32  and  33 , and cutaway portions  34  and  35  give catch member  28  a generally U-shaped configuration which opens outwardly away from the base portion  23  thereof. 
     As best shown in FIGS. 2 and 3, locking member  29  is cantilevered from base portion  23  at one end  36 , the other end  37  of which is free. Locking member  29  is preferably formed by cutting or stamping out opening  25  in base portion  23 , the upper portion of which remains uncut to allow locking member  29  to be bent outwardly therefrom. Locking member  29  is also formed with the generally arcuate portion  38  having an extrados surface  39  which faces upwardly in the direction of catch member  28 . As best shown in FIGS. 2 and 4, locking member  29  is centrally disposed relative to catch member  28 , with arcuate portion  38  of locking member  29  extending upwardly toward cutout portions  34  and  35  in catch member  28 . Notably, locking member  29  includes a bulbous intermediate portion  40  which forms a part of the arcuate portion  38  which curves upwardly towards catch member  28 . 
     The operation of tether clasp  22  can best be described with reference to FIGS. 5 and 6. As shown therein, anchor member  21  of the tethering device  19  is generally bell shaped. The outer wall portions  41  of anchor member  21  diverge radially outward from its upper end towards the anchor bell mouth  42  at its lower end. As shown best in FIG. 5, anchor member  21  has a hollow interior, thereby forming an inward recess at its lower bell mouth  42 . In order to secure anchor member  21  to tether clasp  22 , anchor member  21  is inserted between catch member  28  and locking member  29  through channel  34  so as to be seated within cutaway portion  35  of catch member  28 , as shown in FIG.  6 . 
     When anchor member  21  engages tether clasp  22  and is positioned in its releasable locking position, as shown in FIGS. 1 and 6, the upward biasing balance force exerted on anchor member  21  by the balance mechanism  15  through balance cord  20  causes the diverging wall portions  41  of anchor member  21  to engage legs  32  and  33  of catch member  28  adjacent the central cutaway portion  35  thereof. By so doing, the upward balancing force generated by balance mechanism  15  is transferred through anchor member  21  into tether clasp  22  and lower sash  8  of the double-hung window  1 , thereby lessening the manual force required to lift sash  8  to an open position. 
     Upon engaging anchor member  21  with tether clasp  22 , anchor member  21  must move past the arcuate portion  38  of locking member  29 . By pushing locking member  21  through channel  34  of catch member  28 , the lower bell mouth portion  42  of anchor member  21  will engage the extrados surface  39  of locking member  29 . This causes locking member  29  to deflect slightly downward such that the peripheral portions of the lower bell mouth end  42  of anchor member  21  can move past the arcuate portion  38  and snap into releasable locking engagement with catch member  28 . 
     Once the anchor member  21  is seated within the central cutaway portion  35  of catch member  28 , the spring action of locking member  29  will cause it to return to its resting position as shown in FIG. 6, whereby the extrados surface of locking member  29  extends slightly within the recessed lower bell mouth portion  42  of anchor member  21 . Preferably, the spring biasing force of locking member  29  will cause the extrados surface of arcuate portion  38  of locking member  29  to engage the inner walls of bell mouth portion  42  of anchor member  21  and hold anchor member  21  in releasable locking engagement with catch member  28 . It is contemplated, however, that the arcuate portion  38  of locking member  29  may not engage the inner wall surfaces of the bell mouth portion  42 , yet still extend slightly within the bell mouth portion or detent  42  of anchor member  21 , to prevent anchor member  21  from substantial lateral movement, thereby continuing to hold anchor member  21  in releasably locked engagement with catch member  28 . 
     When it is desired to release anchor member  21  from tether clasp  22 , for purposes of window cleaning, repair, etc., applying an outward force to anchor member  21  will cause locking member  29  to once again deflect slightly downward to allow the lower peripheral portions of anchor member  21  to pass over arcuate portion  38  of locking member  29 . Thus, using substantially the same force as for causing locking engagement, anchor member  21  may then be moved through channel  34  in catch member  28  to a free position such as that shown in phantom in FIG.  1 . 
     Through the use of our improved tether clasp and anchoring system for double-hung windows, it is readily apparent that a universal externally mountable counterbalancing system may be installed on new or pre-existing windows, to enhance the performance and ease the operation thereof. The improved accessibility and readily releasable locking engagement of the tether clasp and anchor system provides versatility with respect to both installation and use of such windows. 
     It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts without departing from the scope of the invention which comprises the matter shown and described herein and set forth in the appended claims.