You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
This application claims the benefits of U.S. Provisional Application No. 61/171,604, filed Apr. 22, 2009. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to backlite assemblies for vehicles. 
     BACKGROUND OF THE INVENTION 
     Current power sliding backlite windows in pickup trucks typically employ a modified window regulator type cable and drum system, which is shown at  200  in  FIG. 1 , to pull the moving window from side to side. Cables need to be routed from the rear window to an alternate location, typically behind and below the rear seats, in order to have enough room for the cable drum and motor. Typically the same motor used to power side windows are used to power the backlite. This motor is typically has a stall torque of 7-9 Nm and is designed to lift windows against seal drag and gravity in a side door. Also, the use of a cable requires that the drum spool the required amount of travel onto itself increasing the height of the drum and it&#39;s required packaging space in the vehicle. This mechanism is assembled onto the backlite structure as individual components. 
     There are several problems, however, with these power sliding backlite assemblies. The current assembly relies on an aluminum frame that is overmolded with plastic for appearance. The aluminum frame is expensive as it requires many machining operations following extrusion to allow the moving glass assembly to be inserted into its grooves such that it is retained in the vertical and vehicle fore-aft direction. Also, typically, the backlite assembly is bonded to the vehicle during assembly. In order to accomplish this reliably and consistently, the assembly is best to be applied to the vehicle flange in one direction without any rotation, simply directly onto the vehicle. With the power mechanism as currently employed, methods to keep it from interfering with the adhesive and the vehicle frame are difficult and cumbersome. There is also additional weight and cost of a metal bracket to support the motor drive assembly for mounting to the vehicle. 
     SUMMARY OF THE INVENTION 
     In the first aspect, the backlite drive invention is directed to a separate drive mechanism consisting of a support channel within which slide the moving window. This drive mechanism is separate and self contained from the structure that is attached to the fixed glass panes. The structure attached to the glass is molded to accept the drive mechanism with or without the use of fasteners. The structure provides the necessary styling and water management functions of the assembly. 
     In a particular embodiment of the first aspect, the drive mechanism is driven by a motor attached to a toothed sprocket which drives a toothed belt. This belt may be a flexible metal belt with punched holes, or it may also be rubber with molded teeth. 
     In a particular embodiment of the first aspect, the end of the open loop rubber belt is retained within a body. The belt is wrapped around a body containing corresponding sprocket shapes. The belt is wrapped encircling the body and is inserted within a retaining body that prevents the belt from unwrapping, which prevents the belt from releasing from the retaining body as the belt is pulled upon. 
     In a particular embodiment of the first aspect, the belt is tensioned by springs that apply force between the belt retaining body and a bushing, which is a body that is attached to the moving glass. 
     In a particular embodiment of the first aspect, the bushing is retained in the support channel in the vertical and vehicle fore-aft directions and is permitted to slide in the vehicle cross-car direction. Two bushings, one on either side of the moving window, firmly attach to the moving window such that they provide support in the vertical and vehicle fore-aft directions. 
     In the second aspect, the aluminum rail for the drive mechanism is integrated into the support structure of the fixed windows. Formed from structural plastic, the lower support rail can provide the guiding channel for the sliding window as well as meet styling and water management requirements. The drive mechanism assembled with the lower structural rail is ready to bond to the fixed window elements of the backlite. 
     In the third aspect, the motor gear housing is integrated into the support structure of the fixed windows. Formed from structural plastic, the lower support rail can provide the guiding channel for the sliding window, meet styling and water management requirements, and integrate the motor gear box. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described by way of example only with reference to the attached drawings, in which: 
         FIG. 1  is a perspective view of an electric power slider in accordance with the prior art; 
         FIG. 2  is a perspective view of backlite assembly in accordance with an embodiment of the present invention; 
         FIG. 3  is a perspective view of a power sliding mechanism that is part of the backlite assembly shown in  FIG. 2 ; 
         FIG. 4  is a perspective view of structural supports and fixed window parts of the backlite assembly shown in  FIG. 2 ; 
         FIG. 5  is a sectional perspective view of an aluminum channel attached to a structural plastic window support which are part of the structural supports shown in  FIG. 4 ; 
         FIG. 6  is a perspective view of a sprocket and belt driving a sliding bushing which is part of the power sliding mechanism shown in  FIG. 3 ; 
         FIGS. 7   a  and  7   b  are perspective views of a bushing assembly engaged in a sliding channel that is part of the power sliding mechanism shown in  FIG. 3 ; 
         FIG. 8  is a sectional view of the bushing assembly shown in  FIGS. 7   a  and  7   b  engaged in the sliding channel showing the belt connected thereto, showing belt tensioning capability and connection to the movable window; 
         FIG. 9  is a perspective view of a backlite assembly in accordance with another embodiment of the present invention; 
         FIG. 10  is a perspective view of a backlite assembly in accordance with yet another embodiment of the present invention; and 
         FIG. 11  is a sectional view of another bushing assembly engaged in the sliding channel showing the belt connected thereto, showing belt tensioning capability and connection to the movable window. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference is made to  FIG. 2 , which shows backlite assembly  10  in accordance with an embodiment of the present invention. The backlite assembly  10  includes first and second fixed windows  25   a  and  25   b , a movable window  14 , a self-contained power sliding mechanism  11 , and a support structure  16 . 
     The first and second fixed windows  25   a  and  25   b  may be captured in any suitable way by the support structure  16 , such as by an adhesive in a groove in the support structure  16 . The movable window  14  is driven by the power sliding mechanism  11  between a closed position shown in  FIG. 2  and an open position (not shown). The power sliding mechanism  11  is self-contained and is supported on the support structure  16  so that the process for assembling the backlite assembly  10  and for installing it on a vehicle is relatively simple. 
     Reference is made to  FIG. 3 , which shows the power sliding mechanism  11  prior to mounting to the support structure  16 . The power sliding mechanism  11  includes a motor assembly  30 , a belt  45  ( FIG. 6 ), and a pair of bushing assemblies  40 , shown individually at  40   a  and  40   b . The motor assembly  30  includes a motor  100 , which drives a worn gear (shown at  101  in  FIG. 10 ), which in turn drives an output gear  102  ( FIG. 6 ). The output gear  102  is integrally connected to a drive sprocket  51 , and both rotate together about a first end axis  104 . Referring to  FIG. 3 , the motor assembly  30  is attached to a first end  103  of a guide rail  32  that contains a slide channel  33 . The guide rail  32  may be made from any suitable material such as aluminum. In this disclosure the term aluminum is intended to encompass any metallic material that includes aluminum, including for example a pure aluminum material and an aluminum alloy. 
     The bushing assembly  40   a , which may be referred to as the first bushing assembly  40   a  slides in the channel  33  and is connected on a first side  105  ( FIG. 2 ) of the movable window  14 . The bushing assembly  40   a  is connected to a first end, shown at  106  in  FIG. 8 , of the belt  45 . The connection may be by any suitable means. For example, the bushing assembly  40   a  may include a bushing body  108 , a belt end retainer  110 , a belt end retainer biasing member  112 , and a connector  114  for connecting with the carrier, shown at  116 , for the movable window  14 . The bushing body  108  has an interior cavity  118  with a first end  120  and a second end  122 . A slot  124  extends through from the exterior of the bushing body  108  to the first end  120  of the interior cavity  118 . The belt end retainer  110  is movable within the interior cavity  118  and is biased towards the second end  122  by the belt end retainer biasing member  112 , which may be any suitable biasing member such as a compression spring. The belt end retainer  110  has a slot  126  that aligns with the slot  124  in the bushing body  108 , and a retaining aperture  128 . The end  106  of the belt  45  is folded over a locking member  47 . Teeth, shown at  130  from the belt  45  mate with grooves  132  in the locking member  47 . The interior cavity  118  of the bushing body  108  is open on both sides and the slots  124  and  126  in the bushing body  108  and belt end retainer  110  are open on one side, so that the folded first end  106  of the belt  45  together with the locking member  47  may be slid laterally into the retaining aperture  128 , in which it fits snuggly, while the belt  45  itself slides into the slots  126  and  124 . The term ‘laterally’ in this particular instance refers to a direction that is perpendicular to the direction of travel of the bushing assembly  40   a  and of the belt  45 . The belt  45  thus extends out from the bushing body  108  through the mouth of the slot  124  to the drive sprocket  51  ( FIG. 6 ). As a result of the locking member  47  and the retaining aperture  128 , the belt  45  is prevented from slipping relative to the locking member  47  and remains locked in the bushing assembly  40   a  and cannot be pulled out through the slot  124 . 
     By biasing the belt end retainer  110  towards the second end  122  of the interior cavity  118 , tension is maintained on the belt  45 . 
     The connector  114  may be made up of any suitable structure. For example, the bushing body  108  may include a slot  134  which receives a clevis  136  that is part of the carrier  116  for the movable window  14 . A removable pin  140  passes through the bushing body  108  and through the clevis  136  to connect the bushing assembly  40   a  to the carrier  138  and therefore to the movable window  14 . 
     The bushing assembly  40   a  may further include a bumper  44  which acts to reduce impact forces and noise at the extremes of travel of the movable window  14 . It is additionally or alternatively possible to provide a stop bumper  44  on the rail  32  or in a suitable place on the support structure  16  for the same purpose. 
     With reference to  FIG. 7   a , the bushing body  108  includes a pair of support grooves  140  (one support groove  140  on each side of the bushing body  108 ), each of which captures a support rib  142  ( FIG. 7   b  and  FIG. 5 ) on each side wall  144  ( FIG. 5 ) of the guide channel  33 . Thus the support ribs  142  slidably support the bushing assembly  40   a , and as a result the surface area of contact between the bushing assembly  40   a  and the guide channel  33  is relatively small. As a result, by sliding on the support ribs  142  lower frictional drag is incurred as compared to a bushing assembly that slides on the entirety of its lower surface. The carrier  138  ( FIG. 8 ) for the movable window  14  also may slide on the support ribs  142  to similar advantage. 
     Additionally, the bushing body  108  includes a pair of side contact strips  146 , (one on each side). These contact strips  146  extend outward from the bushing body  108  to engage the side walls  144  of the channel  33  during sliding of the bushing assembly  40   a  in the channel  33 . These contact strips  146  are relatively thin and thus have a relatively small surface area, so that the frictional drag generated by their engagement with the side walls  144  is relatively small. 
     The belt  45  ( FIG. 6 ) extends out from the slot  124 , over to the drive sprocket  51 , around the drive sprocket  51 , along the channel  33  ( FIG. 8 ) underneath the bushing assembly  40   a  to a second end  148  ( FIG. 3 ) of the rail  32 , around the idler  50  (which may be, for example, a pulley, a sprocket, or a fixed low-friction arcuate bearing surface) at the second end  148  of the rail  32 , and finally, over to the second bushing assembly  40   b . The second bushing assembly  40   b  ( FIG. 11 ) may have the same structure as the first bushing assembly  40   a  ( FIG. 8 ) but retains the second end, shown at  150  in  FIG. 11 , of the belt  45 . The second bushing assembly  40   b  is connected to a second side  152  of the movable window  14 . 
     The motor  100  drives the drive sprocket  51 , which in turn drives the toothed belt  45 . The motor  100  is a bi-directional motor and is thus capable of moving the belt  45 , and accordingly the movable window  14 , in two directions (ie. from its closed position to its open position and from its open position to its closed position). 
     Reference is made to  FIG. 4 . The support structure  16  is made up of an upper support  21  and a lower support  22 . The upper and lower supports together support the fixed windows  25   a  and  25   b , the movable window  14 . The lower support  22  additionally supports the power sliding mechanism  11 . 
     The upper and lower supports  21  and  22  may be made from any suitable material such as a suitable polymeric material, such as glass reinforced polypropylene or glass reinforced nylon. The upper and lower supports  21  may be made by any suitable means such as by injection molding. 
     Seals  26  are provided to seal between the respective inboard edges of the fixed windows  25   a  and  25   b  and the movable window  14 . 
     Reference is made to  FIG. 5 , which shows a sectional view of the lower structural support  22  and the guide rail  32 . The lower structural support  22  includes a groove  156  which receives a tongue  158  on the guide rail  32  in a friction fit, so that the guide rail  32  is retained in the support  22 . Adhesive may be used to ensure that the guide rail remains fixed in position during use. Optionally, fasteners (eg. screws) could be used to more securely affix the guide rail  32  to the support  22 . The support  22  also has a seal  26  mounted thereto for sealing against the movable window  14 . The upper structural support  21  includes similar structure to the lower structural support  22 . 
     It will be noted that the power sliding assembly  11  does not extend beyond the periphery of the backlite assembly  10  and is thus contained substantially within the periphery of the backlite assembly  10 . The periphery is shown at  169 , and is the outer edge of the subassembly comprising the fixed windows  25  and the upper and lower supports  21  and  22 . As a result of this compact arrangement, the entire backlite assembly  10  may be insertable as a single assembly into a window opening in a vehicle having a periphery that is substantially the same size as the periphery  169  of the backlite assembly  10 , which would result in relatively simple installation procedure. 
     Reference is made to  FIG. 9 , which shows a perspective view of a backlite assembly  170  that is similar to the backlite assembly  10  ( FIG. 2 ) but which has a lower structural support  172  that has integrally formed therein a guide rail  13  with a guide channel  174  that supports the sliding movable window  14  and the bushing assemblies  40   a  and  40   b  in similar manner to the channel  33  in the embodiment shown in  FIG. 2 . The lower support  172  may be made from a structural polymeric material, such as glass reinforced polypropylene or glass reinforced nylon, which has the guide rail and guide channel  174  integrally formed therein. Alternatively, the lower support  172  may be formed by overmolding polymeric material on an aluminum guide rail which has the channel  174  therein. By forming the channel  174  integrally in the lower structural support  172 , there is no need to provide a separate guide rail  32  which would then have to be mounted to the structural support. In this way, assembly steps&#39; are eliminated. In this embodiment, the motor assembly  30  is mounted directly to the lower support  172 . 
     Reference is made to  FIG. 10   a , which shows a perspective view of a backlite assembly  180  that is similar to the backlite assembly  170  but which has a lower structural support  182  with a guide rail and a guide channel  184  integrally formed therein, and with a housing  185  for the motor assembly, shown at  186  in  FIG. 10   b , integrally formed therein. In this way, the motor assembly  186  is more securely supported and protected from damage than the cantilevered motor assembly  30  in the embodiment shown in  FIGS. 2 and 9 . In the embodiment shown in  FIG. 10 , the lower support  182  may have the channel  184  formed therein. 
     It will be noted that the motor assembly  186  is provided proximate the closed position of the movable window  14 . This is advantageous in that it permits the open position of the movable window to be positioned closer to the periphery  188  of the backlite assembly  180  than would be possible if the motor assembly were positioned proximate the open position of the movable window  14 . 
     The backlite assemblies described herein can be assembled substantially fully and can be shipped from the manufacturer to the OEM for installation in a vehicle with relatively little work. It may be possible to keep them in their assembled state and insert them as one piece into the window opening of the vehicle. 
     In the exemplary embodiments shown and described two fixed windows  25   a  and  25   b  are included in the backlite assembly. It is alternatively possible to provided some other number of fixed windows. For example, a single fixed window could be provided which would occupy one side of the window opening and a movable window would occupy the other side of the window opening. The movable window would not necessarily occupy 50% of the width of the window opening. 
     While the above description constitutes a plurality of embodiments of the present invention, it will be appreciated that the present invention is susceptible to further modification and change without departing from the fair meaning of the accompanying claims.

Summary:
In an aspect, the invention is directed to a backlite assembly for a vehicle such as a pickup truck. The backlite assembly incorporates a motor assembly and a motor driven belt engaged with a guide rail that can be mounted to a structural support that is bonded to the fixed windows of the backlite assembly. A motor driven belt is used to actuate a movable window between closed and open positions. The lower support can also integrate the rail directly therein. The lower support can additionally integrate a housing for the motor assembly.