Support and counterbalancing of heavy sash that are laterally removable from between opposed jambs of a window.
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 '795 patent and the '279 patent, but the new solution of this invention offers improvements on the performance provided by the '279 patent and the '795 patent.
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.
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 '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
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
In the position shown in
Besides the preferred pivoting of sash support arms 20 on the stiles of sash 10, as illustrated in
As best shown in
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
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
In the basic embodiments illustrated in
In the preferred embodiment illustrated in
Fasteners are also provided to hold rear extensions 1A in latched position over interlock members (pins 2A). In the preferred embodiments illustrated, these fasteners include notches 1B near the ends of extensions 1A that snap into spring loaded snaps 30B provided in improved shoes 30A. The fastener formed by the combination of notches 1B and snaps 30B 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 1C is provided in improved hooks 1 for the insertion of a screw driver head or other tool to force the release of notches 1B from snaps 30B 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.
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Number | Date | Country | |
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20050166461 A1 | Aug 2005 | US |