Abstract:
A retractable window covering for arched or palladian style windows. The covering has a pair of shade members that can be remotely operated by an activator such as a pull cord for opening and closing the shades. The shade members are suspended from a carriage that is movable within an arched track. The shade members can be drawn along the track in opposite directions independently from a horizontal retracted position to an expanded position such that the shade members meet at the apex of the arched window. The present invention includes an embodiment that includes a shield to cover a portion of the drive assembly resting on the window sill or other horizontal surface.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a retractable covering for arched windows. More specifically, the invention is a shade assembly for arched windows which can be opened and closed without manually moving the shade. 
     Many new buildings and homes are designed with arched windows or palladian style windows and doors. Today, there are several types of coverings available for arched windows, but many tend to be either permanently fixed, that is, not retractable, or they are manually opened and closed. While there do exist several retractable style arched window covers, these designs lack aesthetic appeal, which can severely diminish their value as a decorative item, or they are too cumbersome to use, especially for larger diameter arched windows. Due to design limitations, retractable window coverings are not available for arched windows having relatively large diameters. In addition, the mechanisms may be relatively complex or unattractive. 
     For instance, U.S. Pat. No. 4,699,195 and U.S. Pat. No. 4,776,380, both issued to Lance Lester, disclose a shade for use in an arched window. The shade includes a U-shaped frame with two sets of blades, each fanning out from a respective side of the frame. The blades meet at the top of the arched frame where they are latched together to hold the blades in place. The patents to Lester do not disclose a shade that can be remotely operated. 
     U.S. Pat. No. 5,117,889, issued to David G. Coe, discloses an arched window shade constructed of multiple slats strung together which pivot either manually or mechanically from a rigid base to cover the window. The Coe apparatus has relatively complex structure and does not appear to cover the entire arched window. 
     U.S. Pat. No. 5,159,966, issued to Ron Fleishman et al. describes a fan-type arched window covering having compression plates which engage the opposed sides of radial pleats. Compression plates engage the opposed surfaces of the radial pleats to partially compress and rigidify the pleats. Further, the plates enable adjustment of the pleats to accommodate irregularities in the window casing with the blind supporting itself. The patent to Fleishman et al. does not disclose a window covering which can be folded or opened. 
     U.S. Pat. No. 5,794,680, issued to Xue discloses a retractable arched window covering. A pleated fan-style shade is attached to a hub rail on the center portion of a base attached a window sill or the like. The base hides the retracted covering, which stacks on one side of the window. The shade is suspended from an arched track member. A single activator such as a pull cord operates the shade, pulling from one side of the base to the other to completely cover the window. In another embodiment, there are two shades which are stacked on separate sides of the window. However, the patent does not disclose a covering that does not require specially-made shade members. 
     Consequently, there remains a need for a retractable shade assembly having a cover that can be remotely operated to in order to open or close the cover. Preferably, the covering hides the unattractive mechanical elements of the invention that are in plain view to give it an aesthetically pleasing appearance. The covering may be capable of diffusing or blocking sunlight while the covering is in the closed position. Furthermore, the covering preferably accomplishes these goals using a relatively simple mechanical assembly, and with shade members that are readily available with little or no modification. 
     SUMMARY OF THE INVENTION 
     A retractable window covering for covering an arched window is presented. Generally, the window covering includes an arched track having an interior channel. A carriage that is movable within the interior channel of the arched track has a shade member attached thereto. The carriage is attached to a drive assembly which may be remotely operated. 
     The drive assembly forms a closed loop and is disposed within the interior channel of the track. The drive assembly may be a dual chain/cable combination that extends along the arched track diameter and through the track. The drive assembly further includes two sprocket-and-pulley assemblies, one attached to each side of the track, to engage each chain/cable combination used to operate the respective shade members. In other aspects of the invention, gear assemblies are attached to the sprocket-and-pulley assemblies so that the shades may be opened and closed with relative ease. 
     In operation, a rotation device used to activate the drive assembly may be accessed from each side the track. In one embodiment, a pull cord remotely operates the shade member located on that side of the track. The shade member may be open or closed partially or completely, depending on the desired effect. 
     While the present invention is particularly useful in covering arched windows, the components used should not be deemed to limit the application of the present invention. The present invention may be advantageously adapted for use where similar performance capabilities and characteristics are desired. These and other objects and advantages of the present invention will become apparent from the detailed description, claims, and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front elevational view of a window covering constructed according to a preferred embodiment of the present invention, showing the window covering in an open position to allow direct light to pass through the window. 
         FIG. 2  is a front elevational view of the window covering shown in  FIG. 1 , showing the window covering in a closed position. 
         FIG. 3  is a front elevational, partially fragmented view of the window covering shown in  FIGS. 1 and 2 , showing further detail of the window covering assembly. 
         FIG. 4  is a partial perspective view of the window covering shown in  FIG. 1 , showing the sprocket, gear and rotator assemblies in relation to the track. 
         FIG. 5  is a top plan view, partially in section, of a portion of the window covering shown in  FIG. 1 , showing an embodiment of the driving apparatus, particularly how the chain and cables engage sprocket and rotator assemblies. 
         FIG. 5   a  is a side elevational view of the driving apparatus shown in  FIG. 5 . 
         FIG. 5   b  is a top plan view of the driving apparatus shown in  FIG. 5 . 
         FIG. 6  is a perspective view, partially exploded, of the driving apparatus shown in  FIG. 1 , specifically showing the clip member and carriage. 
         FIG. 7  is a partial plan view of the carriage shown in  FIG. 6 , connected to a cable and chain. 
         FIG. 8  is a partial cross-sectional view of the carriage shown in  FIG. 6 , showing its relationship to a cable and chain and the track. 
         FIG. 9  is a partial cut-away view of the window covering shown in  FIG. 1 , specifically showing how the chains and cables are oriented within the track. 
         FIG. 10  is a rear partial cut-away view of the window covering shown in  FIG. 1 , showing the gear assembly in relation to the driving apparatus. 
         FIG. 10   a  is a top cut-away view of the driving apparatus and gear assembly shown in  FIG. 10 . 
         FIG. 11  is a partial side cut-away view of the shade member in relation to the driving apparatus, rotator assembly and the window. 
         FIG. 12  is a partial side cut-away view of the shade member in relation to the driving apparatus, gear and rotator assemblies and the window, and further showing a sill extension member. 
         FIG. 12   a  is a side elevational view of another embodiment of a head rail for the window covering of  FIG. 1 . 
         FIG. 13  is a partial view of the of the window covering shown in  FIG. 1 , specifically showing the clip member attached to the cuff. 
         FIG. 14  is a front perspective view of the sill plate member that is used for windows without sills. 
         FIG. 15  is a side elevational view of the sill plate member shown in  FIG. 14 . 
         FIG. 16  is a partial front view of the window covering shown in  FIG. 2 , showing a pivoting device or set screws used to adjust the gap between the shade members. 
         FIG. 17  is a partial plan view of a temporary compression bracket used to abut two halves of a frame together during installation. 
         FIG. 18  is a front elevational view of the compression bracket shown in  FIG. 17 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 through 18  show various views and embodiments of the retractable arched window covering of the present invention. Referring to  FIGS. 1 and 2 , the covering  10  preferably includes an arched track  12 , and a drive assembly  14  that operates a pair of shade members  16  so that each shade member can be selectively opened and closed either together with or independently from the other. The track  12  has the capability of fitting into an existing window frame (not shown), and each shade member  16  preferably covers up to one half or more of the surface area of a window  18 . Of course, the invention is not limited to semi-circular windows, but to any window having a substantially circular arc at one edge. 
     Referring to  FIGS. 1 ,  3  and  8 , the track  12  is the primary support structure for covering  10 , and may be constructed from an extruded metal channel that is bent to fit an arched window frame. Most preferably, the track  12  is an aluminum alloy because it is easily workable and has a relatively high strength-to-weight ratio. Track  12  is hollow, enabling it to house a portion of the drive assembly  14 , as described below. As best seen in  FIGS. 3 and 8 , the rear face  13  of track  12  has a slot  20 . Preferably, this slot  20  continues from each end  22  of track  12  up to the track apex  21 . At the apex  21 , there is preferably a bridge  26  interrupting the otherwise continuous slot  20 . The purpose of bridge  26  is to prevent each shade  16  from covering more than one half of the window  18 . However, if desired, a single shade could be used to cover the entire window. In that case, bridge  26  would be omitted from the slot  20 . 
     Referring to  FIGS. 3 and 4 , track  12  may be used in a window frame  30  that includes a sill plate  32 . In this case, the ends  22  of track  12  abut sill plate  32 , and the remaining portion of track  12  conforms to the interior surface  34  of window frame  30 , see  FIG. 4 . If a sill plate  32  is not present, a support bracket is used, as described more fully below. 
     Referring now to  FIGS. 3 through 5 , the drive assembly  14  has several components, preferably: a pair of chains  40 , each connected to a corresponding one of two cables  42 ; a tension adjuster  44  for connecting together, and adjusting the tension of, each chain/cable combination; a pair of carriages  46 , each capable of moving one of the chains  40  and corresponding cables  42  within the track  12 ; a pair of driving apparatuses  50 , one located at each end  22  of the track  12 , and preferably, an optional gear assembly  52  corresponding to each driving apparatus  50 ; and a rotator assembly  54  for operation by an activator such as pull cord  56 . 
     Each chain  40  and cable  42  is connected together to form each of two separate and complete loops. Each loop is used to operate a separate shade member  16 . Each loop is positioned in side-by-side relation to the other loop inside the hollow channel of track  12  and further extends between ends  22  of the track. There are two connections for each loop. A first connection between chain  40  and cable  42  may be made by attaching the chain  40  to one end of a tension adjuster  44 , and one end of the cable  42  to the opposite end of the tension adjuster  44 . Most preferably, tension adjuster  44  is a turn-buckle-style adjuster as shown in  FIG. 3 . Of course, other connectors may be used instead of the tension adjuster  44 . The remaining end of cable  42  is attached to one end of a carriage  46 , and the remaining end of the chain  40  is attached to the opposite end of carriage  46 . See  FIGS. 3 and 7 . Preferably, the chain  40  is about 30 to 35 percent of the loop formed by connecting chain  40  to cable  42 . Also, it is preferable to use a coated cable  42  to reduce friction. Suitable coatings for cable  42  include vinyl, TEFLON, plastic or the like. 
     In an alternative embodiment, an optional cover (not shown) may be used to cover the chain  40  and cable  42  that lies exposed on the window sill or window sill substitute. Of course, if the window sill is high enough, the chains  40  and cable  42  cannot be seen when the covering  10  is viewed from the floor. A cover may be constructed from a C-shaped channel or the like and fastened directly to the window sill. 
     Referring now to  FIGS. 6 ,  7  and  8 , in the preferred embodiment, the carriage  46  may be made of a chassis  60  having four wheels  62  connected to it, one to each corner  64  of the chassis. Preferably, each corner  64  is recessed with respect to the exterior sides  66  of the chassis  60 . The top of chassis  60  has a recessed channel  68  running the length thereof. The purpose of channel  68  is to accommodate both sets of chains  40  and cables  42 , as described herein. On one of the sides  66  is an elongated recess  70  for receiving a clip member  74 , described below. As shown in  FIG. 7 , an aperture  72  extends from the recess  70  to the channel  68 . Aperture  72  receives a fastener (not shown) for attaching the clip member  74  to the chassis  60 . 
     Chassis  60  may be machined from a material such as metal (e.g. aluminum alloy) or molded from a material such a plastic. The wheels  62  are preferably made from a non-metal material. Alternatively, carriage  60  may be constructed from a single part that does not have wheels (not shown). For example, carriage  60  could be made from TEFLON, nylon, or any suitable material that can slide through track  12 . 
     As best seen in  FIG. 7 , most preferably, there are two sets of apertures located on the floor  75  of chassis  60  (only one set is actually shown in  FIG. 7 , apertures  76  and  80 ). There is a first set of apertures located on one side of floor  75 , and a second set of apertures are located on the opposite side of floor  75 . The two sets of apertures may be staggered to avoid interference between any connectors used to connect drive assembly parts to the chassis  60 . For example, when carriages  46  are located adjacent to one another at the top of track  12 , connectors attached to the top of chassis  60  could interfere with the closing of the shade members  16 . Preferably, each set of apertures are aligned with the longitudinal axis of carriage  46 . For the first set of apertures, a first chain  40  is connected with a fastener  82  at a corresponding aperture, and a first cable  42  is connected with a fastener  78  at the other corresponding aperture. Preferably, the second set of apertures are aligned with a second cable  42  as shown. Of course, each carriage  46  needs only one set of apertures, but having a second set available omits the need for two separate inventories of carriages. 
     Only a single chain  40  and corresponding cable  42  is connected to a single carriage  46 —both such connections being made on a single side of the carriage chassis  60 . Because there are up to two carriages  46  residing in a single track  12  having a single channel, the first carriage  46  has room within its carriage channel  68  to accommodate the second cable  42  attached to the second carriage  46 , and vice-versa. For example, as the first carriage  46  moves within the hollow track channel, the second cable  42  remains undisturbed.  FIG. 8  is a cross-sectional schematic view of track  12  containing a first carriage  46 , the first carriage having a first chain  40  attached thereto. Adjacent first chain  40  is a second cable  42  that is attached to a second carriage  46  (not shown). The clearance between second cable  42  and first carriage  46  is large enough so that there is no interference between these two components which would hinder movement of the first carriage  46 . 
     Referring to  FIGS. 5 and 5   a–b , chain  40  engages a driving apparatus  50  that may be generally constructed from a sprocket  92  and an idler pulley  94  contained within a sprocket housing  90 . Sprocket  92  is connected to a rotatable drive shaft  93  that is supported by bushings  95  and a drive shaft support  97 . The pulley  94  may be slip fit onto the hub of sprocket  92  so that it can rotate on the sprocket. As seen best in  FIG. 5   a , side  91  of housing  90  is truncated so that sprocket  92  and idler pulley  94  can extend outside of housing  90 , allowing chain  40  to enter housing  90  adjacent side  91 , wrap around sprocket  92 , and exit housing  90  from an inlet  89  located at a surface opposite of surface  91 . Likewise, a second cable  42  may enter housing  90  at the aperture located adjacent to side  91 , wrap around idler pulley  94 , and exit housing  90  from the inlet  89 . As seen in  FIG. 1 , a driving apparatus  50  is preferably located at each end  22  of track  12 . Of course, if only a single shade member were used, only one driving apparatus  50  would be needed. 
     In the most preferred embodiment of the present invention, a gear assembly  52  engages the driving apparatus  50  to reduce the amount of effort needed to operate shade member  16 . Referring to  FIGS. 9 ,  10 , and  10   a , gear assembly is housed in a gear housing  100 . A large gear  101  is connected to the common shaft  102  that is supported by bushings  103 . A reduction gear  104  engages large gear  101 , and is connected to a drive shaft  93   a . Drive shaft  93   a  is supported by bushings  95   a  and  95   b  and by a drive shaft support  97 . A gear reduction of 12/34 or 0.352 is preferred, but other gearing reductions are possible. Further, other types of gear configurations may be used. 
     The drive assembly may be constructed from other elements than a chain and cable. For example, the entire loop could be formed by a chain. Alternatively, other types of cords or ropes could be used (e.g. timing cable or bead chain). Of course, for cords or ropes may not be able to engage a sprocket as described above. Sprocket alternatives would be necessary. For instance, a narrow band could be used in conjunction with friction wheels, or a cable drive could be used in conjunction with knurled pulleys. Preferably, the components that occupy track  12  are made of material that creates too much friction against the track. Too much friction would unnecessarily increase the force required to open and close the shade members  16 . 
     Referring to  FIGS. 4 and 5 , a rotator assembly  54  is attached to the drive shaft  93  of driving apparatus  50  or the drive shaft  93   a  of gear assembly  52 . With either embodiment, rotational movement of sprocket  92  occurs when pull cord  56  is pulled. The rotation of sprocket  92  causes the movement of the chain  40  engaged thereto. The rotator assembly  54  preferably includes a housing  112  with a cover member  114 . Inside the housing member  112  is a pulley hub  116 . Pulley hub  116  has a connecting surface  118  which engages an activator such as pull cord  56 . The cover member  114  keeps the pulley hub  116  in place and hides the internal workings of the rotator assembly  54 . Preferably, pull cord  56  is a continuous loop. 
     In another embodiment of the present invention, the rotator assembly may be a motor (not shown) instead of a pulley operated by a pull cord. Any activator that can be used to rotate the driving apparatus is appropriate. 
     Referring to  FIGS. 4 and 6 , each shade member  16  may be attached to a carriage  46  with an attachment arm such as clip member  74 . Preferably, clip member  74  has an L-shaped arm  120  with a forked slot  122  on the shorter portion of the arm  120 , and a shoulder  124  extending from the longer portion of arm  120 . Forked slot  122  is preferably a groove that has a narrower elongated slit extending into the arm  120  at the apex of slot  122 . Shoulder  124  is shaped to fit into the recess  70  located on the carriage  46 . An aperture  126  extends through the clip member, and is aligned with the aperture  72  (located in recess  70 ) so that the clip member can be fastened to carriage  46  with a fastener (not shown). Clip member  74  may be machined from a material such as metal (e.g. aluminum alloy) or molded from a material such a plastic or the like, and acts as a quick release device for easy shade member removal. 
     Referring to  FIGS. 4 and 12 , cuff  130  is a short bracket that may wrap around an edge of a head rail  132  of shade  16 . Cuff  130  is used when it is undesirable to modify the shade member for attachment to clip member  74 . Cuff  130  has a fastener  134  attached thereto so that is extends outwardly toward track  12 . Fastener  134  has a head and a necked portion, the necked portion fitting into the slot  122  of clip member  74 . Preferably, fastener  134  selectively snaps in and out of slot  122  so that the shade member can be easily removed and replaced from the window. Shown in  FIG. 13  is a close-up view of cuff  130 , wherein a cotter pin  136  keeps the fastener  134  from falling out of slot  122 . As seen in  FIGS. 4 and 13 , cuff  130  may vary in length. Further, cuff  130  may have different profiles that are adaptable to the head rails of various shade manufacturers. 
     In an alternative embodiment, cuff  130  is not used, and the fastener  134  is attached directly to the head rail  132 . Referring to  FIG. 12   a , a head rail  132   a  (head rail profile may vary) has an aperture  133  therein where fastener  134  is attached. Preferably, aperture  133  is threaded. A washer  135  may be used to prevent the clip  74  from contacting  132   a  directly. By preventing direct contact, head rail  132   a  will not become marred by clip  74  in the raising and lowering of shade member  16 . 
     Shade member  16  may be constructed from expandable shades that can be compressed on one side while being stretched on an opposite side. Thus, shade member  16  is preferably a pleated shade, or cellular shade having single, double or triple cells. A double cellular shade is most preferred, however, any shade having adequate stiffness to prevent sagging may be used. Shade members  16  are commonly available rectangular shades, and may be obtained from various commercial shade manufacturers such as HUNTER DOUGLAS, GRABER, AMERICAN and the like. This way, it is possible for the home owner to match the shade member  16  to the rest of the window coverings used in the home. This is a distinct advantage, especially if the other window coverings used in the home have a distinctive color or texture. Commercially available shades have some type of head rail  132 , as mentioned previously, and a bottom rail  138  (which is typically the top rail if the shade  16  were hung in a rectangular window). The head rail  132  is the movable edge, and the bottom rail  138  is a static edge. 
     Each bottom rail  138  may rest on a sill  32  or the like as seen in  FIGS. 11 and 12 . (For windows without sills, another horizontal surface such as a bracket is used, as seen in  FIG. 14 .) Referring to  FIGS. 3 and 11 , some sills  32  are deep enough to accommodate the covering  10 . Preferably, a hub  140  is attached to the sill  32  (or other structure as shown herein) and used to separate shade members  16 . Hub covers  142  may attached to the hub  140  to cover it, and can be designed to be any shape or have any amount of aesthetic value that is desired. Hub covers  142  may be used at both the front and back of the shade member  16  if desired. It is noted that shade members  16  do not necessarily contact the hub  140  as the shade member moves from a stacked position to an unstacked position. Preferably, zero contact is made between hub  140  and shade  16  with the exception of bottom rail  138  to prevent the hang-up of shade member  16  as it moves to the unstacked position. 
     Preferably, the hub  140  has a detent on its bottom surface that aligns with a hub keeper  141  as seen in  FIGS. 3 and 14 . Hub keeper  141  is a plate that is attached to sill  32  or the like. The hub  140  detent is placed over hub keeper  141  so that hub  140  cannot slide about. Preferably, hub  140  may be lifted off for easy cleaning of sill  32 . 
     Referring to  FIG. 12 , some sills  32  are too shallow to completely accommodate covering  10 . In this case, a sill extension such as tray  144  may be used to hide and/or support each cable/chain combination. Tray  144  is preferably a lipped tray that extends between each end  22  of track  12 . 
     Referring to  FIGS. 14 and 15 , some windows do not have sills, and require a support bracket such as sill plate  150 . Sill plate  150  is a substitute for a sill  32 . Sill plate  150  is preferably a flat plate having a front lip  152  angled downward at a right angle and an optional rear lip  154  angled upward at a right angle. Angle brackets  156  may be used to attach sill plate  150  to the window frame (not shown). Sill plate  150  may be attached to the brackets  156  with fasteners  158  as shown. Likewise, brackets  156  may attach to the window frame with fasteners. Sill plate  150  may have other configurations. For instance, the front lip  152  could be extended above the plate, oriented in the opposite direction, or be omitted completely. 
     When the shade members  16  are completely closed as seen in  FIG. 2 , an uneven gap may occur between the head rails  132  near hub  140 . Therefore, it is preferable to attach a pivoting device such as one or a pair of set screws  160  to the top edge of each head rail, see  FIG. 16 . Set screws  160  extend outwardly from head rail  132  towards the gap created therebetween. Changing the extent to which the set screws extend toward the gap can pivot the head rails slightly and cause the gap to be uniform and of a minimal width. The pivot of either shade member occurs at the corresponding connection  133  between the clip member  74  and fastener  134  that extends from the head rail of shade  16 . Preferably, the gap is approximately one millimeter or less in width. One or more detachable or fixed bosses (not shown) may be used instead of adjustable set screws. 
     Referring to  FIGS. 1 ,  11 ,  17  and  18 , to install the covering  10  to a window  18  the following procedure may be used. The channel of track  12  is threaded with the drive assembly. Track  12 , if supplied in two pieces for shipping purposes is assembled on a flat surface such as the floor with the track  12  slot facing downward. To aid in assembly, it is preferable to use a temporary compression bracket  158  to abut the two halves of frame  12  together so that it can be lifted at a unitary piece. Compression bracket is a flat plate  160  that has a pair of clips  162  that can slidably move within a pair of corresponding slots  165  that are located in plate  160 . By placing each clip  162  into the track slots, firmly abutting the two halves of track  12  together, sliding the clips  162  beneath the corresponding slot bridge  26  and toward each other as far as they will go, and finally tightening threaded fasteners  164 , the track can be easily transported to the window frame for permanent attachment thereto. Once the track  12  is attached to the window frame, the bracket  158  can be removed and discarded. 
     So that the track  12  is attached a uniform distance from the window  18  surface, spacers  160  are also temporarily attached to the track  12  at slot  20 . Preferably, the spacers  166  are uniformly sized pegs that have a necked portion that is friction fit into the slot  20 . Spacers are placed along the length of track  20 , preferably at marked intervals. The covering  10  is then placed against the window  18  (or the framing material surrounding the window  18  such as the stop strip  155 , seen in  FIG. 11 ) and track  12  is attached to the window frame. Preferably, the track  12  is attached to the window frame by driving threaded fasteners (not shown) from the track channel through the top surface of track  12  at spaced intervals along track  12 . As seen in  FIG. 4 , access holes  151  at the track inner surface  153  allow the fasteners to be placed within the track channel. 
     Next, each driving apparatus  50  may be adjusted upwardly or downwardly so that they rest against the sill  32  or sill plate  150 . The chain  40  and cables  42  are then connected with the turnbuckle fasteners  44  as described above, and the tension adjusted. The spacers are removed, and the rotator assemblies  54  attached to covering  10 . The hub  140  is centrally placed between the ends  22  of track  12  and fastened to the sill  32  or sill plate  150 . Shade members  16  are set onto the sill or sill substitute and attached to the carriage  46  with the clip member  74 . For easy cleaning, the shade members  16  may be detached from clips  74  and lifted away from the window. Likewise, the hub  140  may be lifted off. 
     In operation, the rotator device is activated, for example, pull cords  56  are pulled separately to raise or lower the corresponding shade member  16 . Each shade member  16  may be closed partially at any distance along the track  12 . 
     Although the invention has been herein shown and described in what is perceived to be the most practical and preferred embodiments, it is to be understood that the invention is not intended to be limited to the specific embodiments set forth above. For example, one shade member may be used instead of two shade members. Further, the covering is not limited to a semi-circular shape as depicted in the drawings. The covering arc could be a significantly less than a quarter-round, or even greater than 180 degrees. Accordingly, it is recognized that modifications may be made by one skilled in the art of the invention without departing from the spirit or intent of the invention and therefore, the invention is to be taken as including all reasonable equivalents to the subject matter of the appended claims.