Patent Abstract:
A sash balance brake shoe assembly ( 2 ) is disclosed for counterbalancing a sash window ( 3 ) slidably supported within a master frame ( 5 ). The assembly generally includes a balance assembly preferably in the form of a block and tackle balance assembly ( 7 ) and a brake shoe ( 28 ). The balance assembly has a balance channel ( 6 ). The brake shoe ( 28 ) has an extension member ( 36 ) that is received by the balance channel ( 6 ). A fastener ( 42 ) directly connects the brake shoe ( 28 ) to the balance channel ( 6 ).

Full Description:
RELATED APPLICATION  
       [0001]    This application claims the benefit of, and is a continuation of, co-pending prior U.S. application Ser. No. 09/875,636, filed Jun. 6, 2001, which is expressly incorporated herein by reference and made a part hereof. 
     
    
     
       TECHNICAL FIELD  
         [0002]    This invention relates generally to a window balance system and more particularly to a block and tackle balance and brake shoe assembly for a sliding sash window.  
         BACKGROUND OF THE INVENTION  
         [0003]    A sash window arrangement disposed within a frame is well known. The frame is comprised of a pair of opposed vertical tracks or jams. The tracks are adapted to slidably guide a pair of sash windows within the frame.  
           [0004]    Various types of balance systems are known and are used to counterbalance the weight of the sash window. In particular, block and tackle counter balance assemblies are known and have become popular due to their combination of relatively compact size and ease of installation. The block and tackle balance combines a system of pulleys and an extension spring mounted within a rigid balance channel for conversion of a high spring tension applied over a short working distance to a lower tension applied over a longer working distance. The extension spring is anchored at one end of the balance channel and the pulley system is anchored at the other end of the channel.  
           [0005]    A traditional arrangement utilizing a block and tackle balance is disclosed in U.S. Pat. No. 5,530,991 to deNormand. In deNormand &#39;991, an end of the balance channel is attached to the track via a hook or other intermediate structure. An end of a cord reeved through the pulley system and extending from a second end of the channel is attached, via a hook or other intermediate structure, to a shoe. This shoe is in turn attached to the window sash and slides therewith, within the track. An inverted block and tackle counterbalance system is disclosed by U.S. Pat. No. 6,041,476 to deNormand. In this arrangement, the end of the cord extending from the channel is attached to the track via a hook or other intermediate structure. The balance channel is then attached to the sash shoe via a hook or other intermediate structure such that the balance channel slides within the track as the window slides within the frame.  
           [0006]    A disadvantage encountered with use of the block and tackle balance system is that it limits the range of slidable motion available to the window sash. This results in ultimately limiting the size of the opening available to an occupant of an enclosure during an event of emergency, such as a fire or other reason necessitating rapid egress. An additional disadvantage realized through use of the prior art block and tackle balance arrangements is that after extended use, the connecting mechanism between the balance channel and the sash shoe, or between the balance channel and the track, may deteriorate. This results in possible sudden detachment of the balance channel from the shoe or the track. If such detachment occurs, replacement of parts or other repairs resulting from the accompanying rapid movement of the block and balance channel and/or sash may be required.  
           [0007]    The present invention is provided to solve these and other problems.  
         SUMMARY OF THE INVENTION  
         [0008]    The present invention provides a block and tackle balance assembly which allows for a greater range of motion of the window sash. The present invention also provides a block and tackle assembly which allows for an improved connection between the brake shoe and the block and tackle balance assembly.  
           [0009]    According to one aspect of the present invention, a sash balance and brake shoe assembly for counterbalancing and locking a slidable sash window within a track is provided. The assembly comprises a block and tackle balance assembly that includes a balance channel formed from a base and a pair of substantially parallel channel walls adapted for slidable mounting within the track. The assembly also includes a brake shoe adapted for slidable movement within the track wherein the brake shoe is attached directly to the balance channel.  
           [0010]    According to another aspect of the present invention, a sash balance and brake shoe assembly for counterbalancing and locking a slidable sash window within a track is provided. The track has a pair of spaced apart, opposed side walls. The assembly comprises a block and tackle balance channel formed from a base and a pair of substantially parallel channel walls adapted for slidable mounting within the track. The assembly further comprises a brake shoe adapted for slidable movement within the track wherein the balance channel is adapted to receive the brake shoe and both the balance channel and brake shoe are adapted to directly fix the brake shoe to the balance channel.  
           [0011]    Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The pivoting and sliding device of the invention will now be described with reference to the accompanying drawings, in which:  
         [0013]    [0013]FIG. 1 shows a perspective view of a double hung window assembly with the present invention shown in phantom;  
         [0014]    [0014]FIG. 2 shows a front perspective view of a sash balance brake shoe assembly of the present invention;  
         [0015]    [0015]FIG. 3 shows a rear perspective view of the sash balance brake shoe assembly of FIG. 2;  
         [0016]    [0016]FIG. 4 shows a partial side view of the assembly of FIG. 2;  
         [0017]    [0017]FIG. 5 shows a front perspective view of the brake shoe of the device of FIG. 2;  
         [0018]    [0018]FIG. 6 shows a rear elevation view of the brake shoe of FIG. 2;  
         [0019]    [0019]FIG. 7 shows a side elevation view of the brake shoe of FIG. 2;  
         [0020]    [0020]FIG. 8 shows a front perspective of a brake shoe of a second embodiment of the present invention;  
         [0021]    [0021]FIG. 9 shows a front elevation view of the brake shoe of a second embodiment of the present invention;  
         [0022]    [0022]FIG. 10 shows a side elevation view of the brake shoe of a second embodiment of the present invention;  
         [0023]    [0023]FIG. 11 shows a rear elevation view a brake shoe of a second embodiment of the present invention;  
         [0024]    [0024]FIG. 12 shows a front perspective view of a balance channel of a second embodiment of the present invention;  
         [0025]    [0025]FIG. 13 shows a partial side view of a partially assembled second embodiment of the sash balance brake shoe assembly of the present invention;  
         [0026]    [0026]FIG. 14 shows a front perspective view of a second embodiment of a sash balance brake shoe assembly embodying the present invention;  
         [0027]    [0027]FIG. 15 shows a rear perspective view of the assembly of FIG. 14;  
         [0028]    [0028]FIG. 16 shows a partial side view of the assembly of FIG. 14;  
         [0029]    [0029]FIG. 17 is a partial side view of a prior art block and tackle assembly connector for a brake shoe;  
         [0030]    [0030]FIG. 18 is a partial front perspective view of a third embodiment of the sash balance and brake shoe assembly of the present invention;  
         [0031]    [0031]FIG. 19 is a partial rear perspective view of the third embodiment of the sash balance and brake shoe assembly of the present invention;  
         [0032]    [0032]FIG. 20 is a partial side elevation view of the third embodiment of the sash balance and brake shoe assembly of the present invention;  
         [0033]    [0033]FIG. 21 is a cross sectional view of the third embodiment of the sash balance and brake shoe assembly of the present invention mounted within a track of a window frame. 
     
    
     DETAILED DESCRIPTION  
       [0034]    While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated.  
         [0035]    [0035]FIG. 1 shows a double hung window assembly  1  having a pair of sash windows  3  slidably disposed in a master frame  5 . Each sash window  3  is comprised of a top sash rail  21 , a base sash rail  23  and a pair of vertical stiles  25 . The master frame  5  has two pair of vertical tracks or shoe channels  4 . Each vertical track or shoe channel  4 , as shown in FIG. 21 is comprised of a rear wall  9 , a pair of lateral walls  15  and a front wall consisting of a pair of shoulders  17 . The shoulders  17  are separated by a slot  19  extending substantially the length of the track or shoe channel  4 .  
         [0036]    A sash balance brake shoe assembly  2  is mounted within the track  4  and provides a counter balance force to sash windows  3 . The sash balance brake shoe assembly  2  generally includes a block and tackle balance assembly  7  and a brake shoe  28  (FIG. 2).  
         [0037]    Referring to FIG. 2, the block and tackle balance assembly  7  generally includes a balance channel  6 , an extension spring  12 , a pulley system comprised of a first pulley block  14  and a second pulley block  16 , and a cord  22 . The balance channel  6  has a base  8 , with an outer surface  27 , and a pair of side walls  10 . Each side wall has a peripheral edge  29  distal from the base  8 . The balance channel  6  further has a first end  18  and a second end  20 . At the first end  18 , the balance channel  6  has a pair of openings  11 , one each located in a respective side wall  10 .  
         [0038]    The extension spring  12  has a hook  13  formed in each end thereof. One end of extension spring  12  is rigidly fixed to the balance channel  6  in the proximity of the first end  18  via a rivet or other suitable connecting means. The first pulley block  14  is rigidly fixed to the second end  20  of balance channel  6  via a rivet or other suitable connecting means. A second end of the extension spring  12 , via the hook  13  formed therein, is attached to the second pulley block  16 . The cord  22  is fixed to the second pulley block  16 , and reeved alternatingly through the first pulley block  14  and second pulley block  16 . A free end  24  of the cord  22  extends out of the balance channel  6  through its second end  20 . Attached to the free end  24  is a jam hook  26  adapted to be connected to track  4 , such connection shown substantially in FIG. 1.  
         [0039]    As shown in FIGS.  5 - 7 , the brake shoe  28  generally includes a slider body  30 , cam  32  and a brake pad  34 . Formed in the slider body  30  is a central opening  31 , adapted to receive the cam  32 . The central opening  31  extends from a front face  39  to the rear of slider body  30 . Guides  33  are formed on slider body  30  to facilitate its sliding motion within the track  4 . The brake pad  34  is adapted to be received by the slider body  30  via a plurality of fingers  35 . The cam  32  receives a pivot bar attached to the window sash  3 . When the window sash  3  is pivoted from the master frame  5 , the pivot bar rotates the cam  32 . Camming surfaces between the cam  32  and the brake pad  34  cam the brake pad  34  into frictional engagement with the rear wall  9  of the track  4 , as is known.  
         [0040]    Integrally formed on the slider body  30  is an extension member  36  having two side surfaces  38  and a rear surface  40 . The extension member  36  is formed to be received by and fit within the first end  18  of the balance channel  6 . The extension member  36  further has a pair of apertures  37 , one each passing through a respective side surface  38 . As shown in FIGS.  2 - 4 , the extension member  36  is positioned within the balance channel  6  wherein the apertures  37  and openings  11  are in registration. A fastener  42  passes through the balance channel openings  11  and through the apertures  37  of the extension member  36  to directly attach the brake shoe  28  to the balance channel  6 . In this way, the rear surface  40  generally abuts the base  8  and the peripheral edges  29  of the balance channel  6 , at the first end  18  are in close proximity to the front face  39  of the slider body  30 . It can also be seen from FIGS. 1 &amp; 2 that in this first described embodiment, the side walls  10  extend away from the base  8  towards the vertical stile  25  of sash window  3 .  
         [0041]    As can be seen in FIGS.  1 - 7 , the brake shoe  28  is adapted to be operably connected to the window sash  3  and slides within the track or shoe channel  4  in response to similar sliding motion of the sash  3  within the frame  5 . As the sash  3  is raised or lowered within the frame  5 , it can be seen that the block and tackle balance assembly  7  provides a counter balance force to the sash  3  to assist in raising, lowering and positioning the sash  3  within the frame  5 .  
         [0042]    It is understood that the fastener  42  may be replaced with any suitable connective means readily known in the prior art including, but not limited to a nut and bolt arrangement, cotter pin arrangement, snap fit or interference fit pin arrangement, or any other removable and/or reusable connective means. Additionally, fasteners or connective means can be conceived that do not pass entirely through both channel side walls  10  that would properly be within the scope of the present invention. For instance, the fastener could consist of a type of gluing or other bonding between the balance channel  6  and brake shoe  28 .  
         [0043]    An additional preferred embodiment is shown in FIGS.  8 - 14 . Elements of the additional preferred embodiment that are substantially similar to corresponding elements of the first described preferred embodiment are referred to using similar reference numbers.  
         [0044]    FIGS.  8 - 11  depict a brake shoe  228  of the second-described preferred embodiment. An extension member  236  integrally formed on a portion of a slider body  230 , is formed to fit within a balance channel  206 . The extension member  236  has a pair of side surfaces  238  and a rear surface  240 . A shoe ear  239  is integrally formed on each side surface  238 . The shoe ears  239  are oblong in shape and extend away from the side surfaces  238  at an oblique angle. Integrally formed in the rear surface  240  is a rear snap  241 . The rear snap  241  is generally triangular in cross section. It is understood that the ears  239  and snap  241  can take a variety of different forms and cross sections.  
         [0045]    As further shown in FIGS.  12 - 16 , the balance channel  206  generally includes a pair of side walls  210  and a base  208 . The base  208  has an outer surface  227 . An oblong slot  243  is formed in each balance channel side wall  210  near a first end  218  of the balance channel  206 . Formed in the base  208  of the balance channel  206  is a generally rectangular snap opening  245 .  
         [0046]    The balance channel  206  is adapted to receive the brake shoe  228  and both are adapted to fix the brake shoe  228  directly to balance channel  206 . The balance channel  206  is passed over the extension member  236  of the brake shoe  228  at a ninety degree angle as shown in FIG. 13. The extension member  236  is then inserted into the first end  218  of the balance channel  206 . This results in the channel side walls  210  spreading apart and then snapping back to their original position as the shoe ears  239  each enter a respective oblong slot  243 . At this point, the brake shoe  228  and the balance channel  206  are in the relative position to one another as shown in FIG. 13. From this position, the brake shoe  228  is rotated in a clockwise direction, as shown in FIG. 13, to a position in line with the balance channel  206 . This in-line position is depicted in FIGS.  14 - 15 . Upon reaching this in-line position, the rear snap  241  passes through the snap opening  245 . It can be seen that the oblong slots  243  and the snap opening  245  cooperate respectively and in conjunction with the shoe ears  239  and the rear snap  241  to directly fix the brake shoe  228  to the balance channel  206 .  
         [0047]    An additional preferred embodiment is shown in FIGS.  18 - 21 . Elements of this additional preferred embodiment that are substantially similar to corresponding elements of the first and second described embodiment are referred to using the same or similar reference numbers.  
         [0048]    The sash balance brake shoe assembly  302  of the third-described preferred embodiment generally includes a block and tackle balance assembly  307  and a brake shoe  328 .  
         [0049]    The block and tackle assembly  307  includes, in part, a balance channel  306 . The balance channel  306  is comprised of a base  308  and a pair of side walls  310 . The base  308  has an outer surface  327 . Each side wall has a peripheral edge  329  located distal from the base  308 .  
         [0050]    The balance channel  306  further has a first end  318 . Located near the first end  318  is a first pair of openings  311 , one each located in a respective side wall  310 . Also located near the first end  318  is a second pair of openings  315 , one each located in a respective side wall  310 . The first pair of openings  311  and the second pair of openings  315  are each located equidistant from the first end  318  of the balance channel  306 . The first pair of side openings  311  is located between the base  308  and the second pair of side openings  315 .  
         [0051]    The brake shoe  328  of the third-described preferred embodiment has an extension member  336  integrally formed on a portion of the slider body  330 . The slider body  330  has a front face  339 . The extension member  336  has a pair of side surfaces  338  and a rear surface  340 . The side surfaces  338  and rear surface  340  are adapted to fit within the second end  316  of the balance channel  306 . The extension member  336  further has a pair of apertures  337 , one each passing through a respective side surface  338 . A brake pad  334  is adapted to be received by the brake shoe  328 .  
         [0052]    The extension member  336  is positioned within second end  316  wherein the apertures  337  and second pair of openings  315  are in registration. A fastener (not shown) similar to fastener  42  of the first described embodiment passes through the second pair of openings  315  of the balance channel  306  and through the apertures  337  of extension member  336 . In this way, the brake shoe  328  is directly attached to the balance channel  306 . As shown in FIG. 19, in the connection of the third-described embodiment, the rear surface  340  of the extension member  336  is positioned opposite the base  308  and is in close proximity to the peripheral edges  329  of the side walls  310 . Also, the outer surface  327  of the balance channel  308  is proximate to and faces the same direction as the front face  339  of the brake shoe  328 .  
         [0053]    [0053]FIG. 21 shows a schematic cross section view of the balance channel  306  located within the track or shoe channel  4 . As can be seen, the outer surface  327  of channel base  308  is adjacent to an inner surface of track shoulders  17  and peripheral edges  329  are adjacent to track base  308 . The channel base  308  also is positioned adjacent the slot  19 . This closes the slot  19  and hides the inner structure of the balance assembly thus providing a more aesthetically pleasing configuration. The brake pad  334  is positioned below the peripheral edges  329  of the balance channel  306 .  
         [0054]    This embodiment also allows the extension member  336  to be positioned within first end  318  such that apertures  337  of extension member  336  are in registration with the first pair of openings  311 . In this configuration (not shown), the rear surface  340  of the extension member  336  is within the balance channel  306  and adjacent to the base  308 , similar to the configuration of the first described embodiment.  
         [0055]    The discussion above regarding the potential alternatives to fastener  42  of the first described embodiment is equally applicable to the fastener of the third described embodiment.  
         [0056]    As can be seen from the above description, the brake shoe of the present invention is directly attached to the balance channel of the block and tackle balance assembly. The advantages of this direct attachment can be seen by reference to FIG. 17, which depicts a typical means of attaching a balance channel  406  to a brake shoe or other structure. This typical means of attachment of the prior art consists of an intermediate structure such as a hook  400 . Use of the hook  400  reduces the range of slidable motion available to the window sash by a distance d. The present invention eliminates the need for intermediate structure to attach the balance channel and brake shoe as these components are directly attached. By virtue of this direct attachment, the distance d is eliminated thereby increasing the range of slidable motion available to a window sash  3 . This increase is critical in that it provides for an increased egress opening available to an occupant of an enclosure during an emergency.  
         [0057]    While the specific embodiments and various details thereof have been illustrated and described, numerous modification come to mind without significantly departing from the spirit of the invention and the scope of protection is only limited by the following claims.

Technology Classification (CPC): 8