Abstract:
A system for supporting a window sash that allows for the removal of the sash from between opposed window jambs. The system supports the window sash through counterbalance shoes supporting sash support arms pivotally attached to the sash. The shoes include hooks which, in first positions, engage lances in the window jambs to hold the shoes in place as the sash is removed from or installed between the window lambs. The hooks, in second positions, engage pins extending from the support arms to retain the support arms on the shoes.

Description:
FIELD OF THE INVENTION 
     Support and counterbalancing of heavy sash that are laterally removable from between opposed jambs of a window. 
     BACKGROUND 
     Large and heavy window sash, such as those used in schools, offices, and institutional buildings, move vertically between opposed pairs of jambs that are generally extruded of metal. A sash for such a window can weigh over 100 pounds so that a counterbalance system for shoes supporting such a sash must exert a corresponding upward lift. Locking the support shoes of the counterbalance system within the jambs must be secure and reliable, because of the large spring forces involved. Also, the sash support must make a heavy sash easy to raise and lower, and removal and replacement of a sash must be convenient and reliable. Since such windows are often used in schools, the counterbalance support system must also be tamper resistant to the manipulations of curious children. Besides these requirements, an effective window system must accomplish all the necessary functions in a reliable way with elements that are inexpensive to manufacture and maintain. 
     This invention improves upon solutions proposed in application Ser. No. 08/839,161 (the aforementioned application being hereby incorporated by reference), now U.S. Pat. No. 6,948,279 B1, and U.S. Pat. No. 5,231,795 for supporting and counterbalancing a heavy sash that is laterally removable from between opposed jambs of a window. The sash counterbalancing and removal problem is the same one addressed in the &#39;795 patent and the &#39;279 patent, but the new solution of this invention offers improvements on the performance provided by the &#39;279 patent and the &#39;795 patent. 
     SUMMARY OF THE INVENTION 
     As in U.S. Pat. No. 6,948,279 the instant system for support of a sash that is laterally removable from between opposed window jambs uses sash support arms that are movably arranged for transferring the weight of the sash to the shoes and for bridging distances between the sash stiles and the shoes. When not supporting the weight of the sash, the support arms move to positions that allow the sash to be lifted off of counterbalance support shoes and laterally removed from between the window jambs and conversely reinserted between window jambs and lowered onto the shoes. This is done while the shoes are locked in positions within the window jambs. When the support arms support the weight of the sash, they are in positions that rest the sash weight on the counterbalance shoes to support the weight of the sash. 
     The counterbalance shoes, which are biased upwardly by counterbalance springs, cooperate with the sash support arms. The shoes receive and support the sash weight transferred to the shoes by the sash support arms, and the shoes have hooks that can be deployed to lock the shoes reliably in the jambs by engaging projections formed in the jambs for this purpose. An improvement taught in the instant application is the provision of support arm latching members on the hooks in the form of rear extensions that latch over interlock pins extending from the support arms when the hooks are disengaged from the jambs. Thus, as taught herein, the same hook elements that serve to hold the shoes in position when engaged to the jambs serve to further secure the support arms for the sash in position on the shoes when disengaged from the jambs. 
    
    
     
       DRAWINGS 
         FIGS. 1 through 5  illustrate a basic embodiment for a system for shoe latching in laterally removable sash in accordance with the teachings of U.S. Pat. No. 6,948,279 and are included for the basic understanding of the underlying system and workings of the instant invention provided thereby. 
         FIGS. 1 through 3  schematically illustrate the removal and replacement of a sash supported by the inventive system of U.S. Pat. No. 6,948,279 with the sash moved laterally for removal or insertion in  FIG. 1 , lifted above or lowered onto counterbalance shoes in  FIG. 2 , and supported on counterbalance shoes in  FIG. 3 . 
         FIGS. 4 and 5  are partially cut-away elevational views showing preferred embodiments of sash support arms and counterbalance shoes of U.S. Pat. No. 6,948,279 with a shoe locked in a jamb in  FIGS. 4  and unlocked from a jamb in  FIG. 5 . 
         FIGS. 6A through 10  illustrated a preferred embodiment incorporating an improved system for shoe latching in laterally removable sash in accordance with the teachings of the instant invention. 
         FIG. 6A  provides a first perspective view of a preferred embodiment incorporating the teachings of the instant invention. 
         FIG. 6B  provides a first side view of a preferred embodiment incorporating the teachings of the instant invention. 
         FIG. 6C  provides a second perspective view of a preferred embodiment incorporating the teachings of the instant invention. 
         FIG. 6D  provides a view from  6 D— 6 D of  FIG. 6B  of the preferred embodiment incorporating the teachings of the instant invention. 
         FIG. 6E  provides a view from  6 E— 6 E of  FIG. 6B  of the preferred embodiment incorporating the teachings of the instant invention. 
         FIG. 7  provides a perspective view of the shoe illustrated in  FIGS. 6A through 6E . 
         FIG. 8  provides a side view of the shoe illustrated in  FIGS. 6A through 6E . 
         FIG. 9  provides a side view of the bracket and support arm illustrated in  FIGS. 6A through 6E . 
         FIG. 10  provides a perspective view of the bracket and support arm illustrated in  FIGS. 6A through 6E   
     
    
    
     DETAILED DESCRIPTION 
     A sash supported according to this invention is laterally removable from between a pair of opposed window jambs in a way that is similar to the sash removal shown in application Ser. No. 08/839,161, now U.S. Pat. No. 6,948,279 B1. The instant system differs from that shown in the &#39;279 patent principally in regard to improvements related to its improved shoe locking hooks  1 . Thus, in the preferred embodiments of the instant application illustrated in  FIGS. 6A through 10 , support arm latching members are provided on the improved hooks  1  in the form of rear extensions  1 A. Rear extensions  1 A latch over new interlock pins  2 A provided in and extending from support arms  201  when the improved hooks  1  are disengaged from their adjacent jambs. Therefore, the same improved hooks  1  that serve to hold improved shoes  30 A in position when engaged to the jambs serve to further secure the support arms  201  for the sash in position on improved shoes  30 A when disengaged from the jambs. In other respects, the preferred embodiments of the instant application and their use can be best understood by review of the more basic embodiment illustrated in  FIGS. 1 through 5  and the teachings of the &#39;279 patent. 
     The operation of a basic embodiment of the inventive system, as described in more detail in U.S. Pat. No. 6,948,279 is shown schematically in  FIGS. 1–3 . Sash  10 , as shown in  FIG. 1 , is lifted off of shoes  30  that are locked in place within jambs  11 , which are illustrated by broken lines extending along the light opening between jambs  11 . For heavy sash that benefit from the inventive support system, jambs  11  are generally extruded of metal to allow lateral room for maneuvering sash  10  in between and out from between jambs  11 . Jambs  11  are essentially the same as jambs used with the sash support system of the &#39;795 patent, and such jambs are available in different dimensions to accommodate different sizes of sash  10  and corresponding counterbalance systems. Sash  10 , in the position shown in  FIG. 1 , is also moved laterally within jambs  11  to free one stile edge of sash  10  from jambs  11  for maneuvering sash  10  out from between jambs  11  or back into a position between jambs  11 . 
     In the position shown in  FIG. 2 , sash  10  is centered between jambs  11  but elevated above locked shoes  30 , as it is lifted off from or lowered onto shoes  30 . In the position shown in  FIG. 3 , sash  10  is again centered between jambs  11 , but is lowered onto shoes  30 , which are no longer locked within jambs  11 . In the supported position shown in  FIG. 3 , sash  10  rests on and is supported by shoes  30  by means of sash support arms  20  that are moved to an outward position. Arms  20  are in inward positions when sash  10  is lifted off of shoes  30 , as shown in  FIGS. 1 and 2 . 
     Besides the preferred pivoting of sash support arms  20  on the stiles of sash  10 , as illustrated in  FIGS. 1–3 , it is also possible to arrange sash support arms that are pivotally mounted on shoes  30 . Preferably a mid region  34  of shoe  30  has a groove that receives and holds a guide block  35 . Guide block  35  gives shoe  30  a smooth running fit within a channel  14  formed behind fins  13  in a rear region of jamb  11  spaced outward from sash  10 . With such an arrangement, shoe mounted sash support arms would pivot inward to engage sash stiles and support the weight of a sash engaged by the arms, which are preferably braced against pivoting when in a support position. Pivoting the support arms on the shoes can thus achieve a similar result to the preferred pivoting of the support arms on the sash stiles. Either way, the support arms transfer the sash weight to the shoes and move from sash support positions when the sash is uplifted from the shoes, to allow lateral movement and withdrawal of the sash from the jambs. 
     As best shown in  FIGS. 4 and 5 , support arms  20  are pivotally mounted on brackets  21  of mounts  22  that are secured to the stiles of sash  10 , which have a recessed edge groove that receives mount brackets  22 . Pivot pins  23  support arms  20  on brackets  21  to pivot between outwardly extending positions shown in  FIGS. 4 and 5 , and downwardly dependent positions shown in  FIGS. 1 and 2 . Each of these positions is limited and braced by mount  22 . In the outwardly extending position, an end  24  of arm  20  abuts against mount  22  to brace arm  20  against pivoting upward. To distinguish between support arms  20  of different lengths, the arms are preferably formed with extruded coding lines  28 . In the downwardly dependent position, an abutment  25  on support arm  20  engages a lance  26  on mount  22  to prevent pivoting of support arm  20  downward or inward beyond the position shown in  FIG. 10 . 
     A lower region  36  of shoe  30  has a sash support platform  37  that is engaged by the ends  27  of sash support arms  20  to uphold the weight of sash  10 . Platforms  37  extend toward sash  10  far enough to engage sash support arms  20  in their inward positions. The extension of platforms  37  towards sash  10  also leaves free room above platforms  37  for sash  10  to be moved laterally while it is raised above platforms  37  and maneuvered out of or into the space between opposed jambs  11 . As a sash  10  is lowered into a supported position on shoes  30 , the ends  27  of support arms  20  first engage inner end regions  38  of support platforms  37 ; and then as sash  10  is further lowered, arm ends  27  slide outward along platforms  37  to the support position illustrated in  FIGS. 4 and 5 . The reverse occurs as sash  10  is lifted up off of shoes  30 . 
     The small step  39  in platform  37  is preferred for resisting lateral movement of sash  10  while resting on shoes  30  and as a positive indication that arm ends  27  of a sash being lowered have reached appropriately supported positions on platforms  37 . The regions where arm ends  27  support sash  10  on platforms  37  are preferably directly below slots  32  where counterbalance elements exert an upward force on upper regions  31  of shoes  30 . This minimizes any moment arms tending to turn shoes  30  around horizontal axes. 
     Below platform  37  is preferably arranged a pivot pin  43  for a shoe-locking hook. In  FIGS. 1 through 5 , illustrating the exemplary teachings of a basic embodiment of the invention (as more thoroughly taught and described in the &#39;279 patent), this shoe-locking hook is hook  45 . Hook  45  has a latching nose  48  that latches into an opening  42  in spring  40 . In the preferred embodiment of the instant invention, as illustrated in  FIGS. 6A through 10 , this is improved hook  1 . In either, a hook end  46  interlocks with a projection or lance  47  formed in jamb wall  12 , as illustrated in  FIG. 4 . 
     In the basic embodiments illustrated in  FIGS. 1 through 5 , the underside of the inward region  38  of support platform  37  has a groove  41  that receives and retains a resilient latch spring  40 . An anchored end  51  of spring  40  can be pressed into slot  41  of the basic embodiment to retain spring  40  frictionally in place. In the basic embodiments, a downwardly extending projection  52  engages spring  40  to prevent movement beyond a resilient latching position, as illustrated. Hook  45  of the basic embodiment has a latching nose  48  that latches into an opening  42  in spring  40 , as illustrated in  FIG. 5 . Latching nose  48  and spring  40  are preferably configured so that shoe-locking hook  45  can be manually pushed into the latched position shown in  FIG. 5 . Unlatching hook  45  for deployment preferably requires pressing a screwdriver blade in between hook end  46  and the free end  49  of spring  40 . This makes the accidental deployment of hooks  45  of the basic embodiment unlikely. 
     In the preferred embodiment illustrated in  FIGS. 6A through 10 , support arm latching members are provided on improved hooks  1  in the form of rear extensions  1 A. At the opposite end of hook  1  from rear extensions  1 A is hook end  461 . Rear extensions  1 A can be latched over interlock pins  2 A provided in and extending from the sides of support arms  201  when the improved hooks  1  are disengaged from their adjacent jambs. (This serves to hold the support arms  201  in place on improved shoes  30 A, supplementing the weight of the sash in accomplishing this purpose). Thus, the same improved hooks  1  that serve to hold improved shoes  30 A in position when engaged to the jambs serve to further secure the support arms  201  for the sash in position on improved shoes  30 A when disengaged and swung away from the jambs and over interlock pins  2 A. 
     Fasteners are also provided to hold rear extensions  1 A in latched position over interlock members (pins  2 A). In the preferred embodiments illustrated, these fasteners include notches  1 B near the ends of extensions  1 A that snap into spring loaded snaps  30 B provided in improved shoes  30 A. The fastener formed by the combination of notches  1 B and snaps  30 B is intended to be, and is, very strong so as to prevent casual release of improved hooks  1  (by, for example, school children). A slot  1 C is provided in improved hooks  1  for the insertion of a screw driver head or other tool to force the release of notches  1 B from snaps  30 B so as to allow improved hooks  1  to attach to adjacent jambs. However, numerous changes can be made in the structure of the foregoing elements (as with other elements herein described) without exceeding the ambit of the inventive concept. Accordingly, it is to be understood that the embodiments of the invention herein described are merely illustrative of the application of the principles of the invention. Reference herein to details of the illustrated embodiments is not intended to limit the scope of the claims, which themselves recite those features regarded as essential to the invention.