A carrier and balance assembly for installation into the jamb channel of a window frame. The carrier and balance assembly are capable of being installed into the jamb channel optionally either as a single assembly or as two separate components. The two separate components are the carrier and a hanger-balance subassembly. The advantage of installing the carrier and balance assembly as two separate components is that such installation can occur after the assembly of the window frame and even after installation of the window into the wall of a building. Once the carrier and hanger-balance subassembly are separately installed in the jamb channel, they are then non-permanently locked together. Should any part of the carrier and balance assembly become damaged, replacement is performed by simply reversing the process described above without having to damage the jamb channel.

FIELD OF THE INVENTION 
     The invention pertains to the field of window sash balance systems. More particularly, the invention pertains to a two piece carrier and balance assembly and method for use with a variety of sash balances. 
     BACKGROUND OF THE INVENTION 
     This invention relates to both single and double hung window systems. Single hung window systems have only a single sash and double hung windows have two sashes, each of which are inserted into jamb channels to enable the vertical movement of the sashes in the window system. A locking pivot facilitates the cleaning and/or removal of each sash by allowing the sash to be tilted with respect to the window frame. Carriers are used to control the vertical movement of the sash throughout the jamb channel and facilitate the pivoting of the sash by lockingly engaging the sash to the jamb channel as the sash is pivoted. The pivot means can be a cylindrical rod or guide pin that inserts into the opening of a rotatable cam located in the carrier. As the cam rotates, it urges locking members forcibly against the walls of the jamb channel to secure the carrier and thus the sash in place. 
     The initial assembly of pivotable windows can be complex. Additionally, in order to replace an aged, broken or malfunctioning carrier or balance, a portion of the jamb channel often must be deformed or entirely removed and replaced to gain access to the defective part. Also, since conventional balance systems consist of an integral balance/carrier assembly, the entire assembly must be replaced even though only one element may be defective. It is desirable, therefore, to provide a carrier and balance system that will facilitate the initial assembly of the window, permit easier removal and replacement of defective parts of the sash balance system once the window has been installed in the wall of a building and allow the replacement of only the defective part rather than the entire carrier and balance assembly. 
     SUMMARY OF THE INVENTION 
     The present invention is a window carrier and balance assembly method for installing the device into or removing it from the jamb channel of a window frame. The carrier and balance assembly contains a carrier having a substantially “T” shaped configuration, a hanger non-permanently secured to the carrier and a balance either permanently or non-permanently secured to the hanger. The carrier contains a rotatable cam with a substantially central opening for engagement with a pivot guide pin connected to each stile of the sash. Diametrically opposed shoulders are located at a first end of the carrier to retain the carrier within the jamb channel. At the other, or second, end of the carrier is a locking tab which inserts into a mating locking channel to non-permanently but securely connect the carrier to the hanger. Shoulders are located at a first end of the hanger to retain the hanger within the jamb channel. A balance is connected to the other, or second, end of the hanger. 
     The carrier and balance assembly can be installed in the jamb channel as a single assembly or as two components. If installation is performed as a single assembly, the carrier, hanger and balance are assembled together prior to being installed in the jamb channel. In this case, the entire assembly is inserted through either end of the jamb channel prior to completing the assembly of the window frame. However, it is preferred that the carrier and balance assembly of the invention be inserted into the jamb channel as two separate components, the carrier being one component and the hanger-balance subassembly being the other component. This method allows assembly of the window frame before the installation of the carrier and balance mechanism into the jamb channel. This method is performed by orienting the axis of the shoulders of the carrier parallel to the axis of the jamb channel, inserting the carrier into the jamb channel and rotating the carrier 90 degrees so that the shoulders are now perpendicular to the axis of the jamb channel. The jamb channel is substantially “U” shaped, having two opposing side walls and a back wall. Each of the open edges of the side walls has a flange bent over at a substantially 90 degree angle to the plane of its corresponding side wall. The flanges run the length of and overhang the entire opening of the jamb channel. As the carrier is rotated 90 degrees after being inserted into the jamb channel, the shoulders abut the flanges in order to prevent the carrier from falling out of the jamb channel. The hanger is connected to the sash balance to form a hanger-balance subassembly by any one of a variety of conventional connection means depending on the design of the balance used. Similar to installation of the carrier, the hanger-balance subassembly is oriented so that the axis of the shoulders of the hanger is substantially parallel to the axis of the jamb channel. After the hanger is inserted into the jamb channel, it is rotated approximately 90 degrees so that the shoulders of the hanger abut the flanges in order to prevent the hanger from falling out of the jamb channel. 
     Once the carrier and the hanger-balance subassembly are separately inserted into the jamb channel, they are ready to be locked together. The first step is to lay the carrier against the back wall of the jamb channel so that its locking tab is oriented toward the hanger. This aligns the locking channel on the hanger with the locking tab on the carrier. The locking tab is inserted into the locking channel and the hanger-balance subassembly is inclined into the jamb channel until the balance portion rests against the back wall. A projection on the carrier operatively engages a ledge on the hanger which non-permanently locks the carrier and the hanger together. 
     In the event that one or more of the component parts of the carrier and balance assembly fails or otherwise becomes defective and must be replaced, the assembly operation can be reversed so that the individual defective part can be removed without damaging the jamb channel. This makes repair of the carrier and balance assembly relatively inexpensive since only the defective part need be removed. It is also easy enough to have the homeowner (or building maintenance personnel) perform the repair, which ultimately saves the window manufacturer the expense of having to send a repairman to the location of the installed window. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows a top plan view of the two piece carrier and balance assembly of the invention with an inverted block and tackle balance. 
         FIG. 1B  shows an exploded top plan view of the inventive two piece carrier and balance assembly of  FIG. 1A . 
         FIG. 2A  shows the two separate parts of the inventive carrier and balance assembly being aligned with the jamb channel of a window frame. 
         FIG. 2B  shows the two separate parts of the inventive carrier and balance assembly after insertion into the jamb channel. 
         FIG. 3  shows an end perspective cross section view of the jamb channel after rotation of the two separate parts of the inventive carrier and balance assembly. 
         FIG. 4  shows one of the steps in the assembly of the carrier and balance assembly after installation in the jamb channel. 
         FIG. 5  shows a further step in the assembly process. 
         FIG. 6A  shows a side perspective view of process of locking of the balance and hanger components. 
         FIG. 6B  shows a cross section of  FIG. 6A . 
         FIG. 7A  shows a partial cut away view after the locking together of the balance and holder components. 
         FIG. 7B  shows a center plane cross section view of after the locking together of the balance and holder components. 
         FIG. 8A  shows the carrier and balance assembly using a conventional block and tackle balance. 
         FIG. 8B  shows the carrier and balance assembly using a conventional spiral balance. 
         FIG. 8C  shows the carrier and balance assembly using a conventional constant force spring balance. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1A and 1B , the window carrier and balance assembly  100  of the present invention is shown. The carrier and balance assembly  100  consists of a carrier  102 , a hanger  104  non-permanently secured to carrier  102  and a balance  106  that is secured to the hanger. The balance shown in  FIGS. 1A through 7B  is a conventional inverted block and tackle balance. However, within the context of the present invention, other balance designs may be used, some examples of which are shown in  FIGS. 8A-8C . The carrier  102  has a first end  102   a  and a second end  102   b . At the first end  102   a  are retention shoulders  108  having an axis ii-ii and locking means that consists of a conventional rotatable cam  105  having a central opening  107  for engagement with a guide pin located on each stile of the sash (not shown). Once the guide pin is inserted into the opening  107  and then rotated by tilting the sash, the cam also rotates. The rotation of the cam causes the locking means to exert an outwardly biasing force against both side walls of jamb channel or, alternatively, against both the back wall and flanges of the side walls, depending on the design of the locking means to temporarily secure the sash in place along the jamb channel. 
     Referring to  FIG. 1B , at the second end  102   b  of carrier  102  is an integral locking tab  110  for insertion into the hanger  104  to non-permanently but securely connect the carrier  102  and the hanger  104  together. Hanger  104  has a first end  104   a  and a second end  104   b . At the first end  104   a  are shoulders  114  which have an axis iii-iii and a locking channel  112 . The shoulders  114  retain the hanger within jamb channel  120 . A first end  118  of the containment shaft  111  of balance  106  is connected to extension  103  located at the second end  104   b  of hanger  104 . Using a conventional inverted block and tackle balance, the hanger  104  and balance  106  may secured together by connection means  116 , which might include, for example, a screw, a rivet, a locking pin or resilient snaps. If the retention means is a screw, the hanger  104  can easily be disconnected from the balance  106  by simply removing the screw. If a locking pin which joins the opposing walls of the balance is used, the second end  104   b  of the hanger  104  may include a cut-out on its side walls to enable the hanger to be angled under the locking pin and snapped into place. Removal is relative easy and is achieved by simply reversing the installation process. If resilient snaps are used, outwardly extending tabs on each of the side walls of the hanger  104  would non-permanently engage mating holes in the side walls of the balance  106 . In this case, removal would require forcing the tabs inward through the holes in the walls of the balance. If, however, a rivet is used as the connection means, the hanger and balance are permanently engaged and removal would require cutting through the rivet. 
     The types of balances  106  that may be used with the carrier and balance assembly  100  of the invention is not limited and are well known in the art. Examples of conventional balances include (see  FIG. 8A ) inverted block and tackle mechanisms, spiral rod/torsion spring mechanisms (see  FIG. 8B ), constant force spring mechanisms (see  FIG. 8C ), elastomeric devices, linear slides or electric powered mechanisms, such as those that might employ a stepper motor. 
     The carrier and balance assembly  100  may be inserted into the jamb channel  120  as a single assembly or as two separate components. If installation is performed as a single assembly, the carrier  102 , hanger  104  and balance  106  are pre-assembled together prior to being installed in the jamb channel  120 . In this process, the entire carrier and balance assembly  100  is inserted through either end of the jamb channel  120  prior to assembly of the window frame. 
     However, referring to  FIGS. 2A and 2B , the preferred means of assembly is by first joining the hanger  104  and the balance  106  into a hanger-balance subassembly  109  and then installing the carrier  102  and hanger-balance subassembly  109  separately into the jamb channel  120 . This method allows for the complete assembly of the entire window frame before the installation of the separate components of the carrier and balance assembly  100  into the jamb channel  120 . This installation method is performed by orienting the axis ii-ii of shoulders  108  of the carrier  102  parallel to the axis i-i of the jamb channel  120 , inserting the carrier into the jamb channel and then rotating the carrier 90 degrees so that the shoulders  108  are now substantially perpendicular to the axis i-i of jamb channel  120 . The jamb channel  120  is substantially “U” shaped, having two opposing side walls  122   a  and  122   b  and a back wall  124 . Each of the open edges of the side walls  122   a  and  122   b  have an integrally formed flange  126   a  and  126   b , respectively, each of which are bent substantially at a 90 degree angle to the plane of its adjoining side wall. The flanges  126   a  and  126   b  run the length of and overhang the opening of the jamb channel  120 . 
     Referring to  FIG. 3 , as the carrier  102  is rotated 90 degrees after being inserted into the jamb channel  120 , the flanges  126   a  and  126   b  abut the shoulders  108  to prevent the carrier  102  from disengagement with the jamb channel  120 . Similarly, the hanger-balance subassembly  109  is oriented so that the axis iii-iii of the shoulders  114  of the hanger  104  is substantially parallel to the axis i-i of the jamb channel  120 . After hanger  104  is inserted into the jamb channel  120 , it is rotated approximately 90 degrees so that the flanges  126   a  and  126   b  of the side walls abut shoulders  114  to prevent the hanger  104  from disengagement with jamb channel  120 . 
     Once the respective shoulders  108  and  114  of carrier  102  and hanger  104  are inserted into the jamb channel  120 , the two components are ready to be locked together. The first step is to incline the carrier  102  so that it lies against the back wall  124  of the jamb channel  120  with its locking tab  110  oriented toward the hanger  104  ( FIG. 4 ). The two parts are then urged together such that the locking tab  110  engages the locking channel  112 . Referring to  FIG. 5 , once locking tab  110  is inserted into locking channel  112 , the hanger-balance subassembly  109  is fully inclined into the jamb channel  120  until the full length of balance  106  rests against the back wall  124 . Referring now to  FIG. 6A , at least one resilient snap  130  on carrier  102  begins to engage a mating protrusion  132  on hanger  104 .  FIG. 6B  is a cross section view of the carrier and balance assembly  100  after the carrier  102  is connected to hanger  104 . A projection  133  on carrier  102  begins to engage a ledge  135  on hanger  104 . Referring now to  FIG. 7B , as the hanger and balance subassembly  109  is fully inclined, the full engagement of the projection  133  with the ledge  135  acts as a fulcrum to facilitate the locking of the resilient snaps  130  with its corresponding protrusion  132  to non-permanently lock together the carrier and the hanger (see  FIG. 7A ). 
     Once the carrier and balance assembly  100  abuts the back wall  124  of the jamb channel  120 , the outer ends of shoulders  108  and  114  of the carrier  102  and hanger  104 , respectively, may establish a 4-point contact with the side walls  122   a  and  122   b  of the jamb channel if the lengths of shoulders  108  and  144  are substantially the same. A 4-point contact may be desirable to substantially reinforce the stability of the carrier and balance assembly  100  with respect to the axis i-i of the jamb channel  120 . The elimination of unnecessary motion helps to keep the various components properly aligned when the carrier is locked. However, if the lengths of the shoulders  108  and  144  are substantially different for reasons that might include harmonization of various components to reduce inventory complexity, then a 4-point contact may not be achieved. 
       FIG. 8A  shows a bobbin  202  of an optional conventional block and tackle balance  200  connected to the hanger  104  of the carrier and balance assembly  100  by connecting means  208 . Cord  204  connects the bobbin  202  to other components of the block and tackle balance (not shown).  FIG. 8B  shows the carrier and balance assembly  100  of the invention connected to the spiral rod  302  of a conventional spiral rod balance  300  by the appropriate connecting means  308 .  FIG. 8C  shows the inventive carrier and balance assembly  100  connected to one end of the spring  402  of a conventional constant force spring balance  400  by appropriate connecting means  408 . 
     In the event that one or more of the component parts of the carrier and balance assembly  100  becomes defective or for some reason must be replaced, the assembly method described above can be reversed so that the individual defective part can be removed without damaging the jamb channel  120 . This makes repair of the carrier and balance assembly  100  relatively inexpensive since only the defective part need be removed. The method of installation and removal of the carrier and balance assembly  100  is easy enough so that the average homeowner (or building maintenance personnel) can perform the necessary repair himself or herself, thus ultimately saving the window manufacturer the expense of having to send a service technician to the location of the installed window to perform the required repair. 
     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.