Abstract:
A roller shade assembly comprises a tubular roller having a generally cylindrical internal cavity, an generally tubular extension telescopically mounted within the internal cavity of the roller tube, and an outer tube mounted over the extension. The extension includes an outer wall and a plurality of winged splines located around the outer circumference of the outer wall which extend along at least a portion of the length of the extension tube.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 61/331,082, filed May 4, 2010 the content of which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The present invention relates to window roller shades, and in particular to length adjustable roller shades. 
     SUMMARY 
     According to one embodiment, a roller shade assembly comprises: a tubular roller having a generally cylindrical internal cavity; a generally tubular extension telescopically mounted within the internal cavity of the roller, wherein the extension comprise an outer wall and a plurality of winged splines located around the outer circumference of the outer wall which extend along at least a portion of the length of the extension; and an outer cardboard tube mounted over the extension. 
     In at least one embodiment, each of the winged splines comprises first and second members splayed outward in opposing directions from a common center point on the outer wall. 
     In at least one embodiment, the first and second members have a curved cross-sectional contour. 
     In at least one embodiment, the first and second members are substantially resiliently flexible. 
     In at least one embodiment, the resiliently flexible first and second members provide for a tight frictional fit that resists lengthwise movement and relative rotation between the extension and the roller, while allowing the extension to slide lengthwise within the roller when under compressive force. 
     In at least one embodiment, the resiliently flexible first and second members allows for the extension to be adaptable for insertion into rollers of varying diameters. 
     In at least one embodiment, the plastic extension is substantially rigid along its length to provide stability to the outer tube. 
     In at least one embodiment, the roller and the outer tube define a substantially continuous single-diameter contour. 
     These and other features of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of this invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of this invention will be described with reference to the accompanying figures. 
         FIG. 1  is an exploded view of the roller shade assembly according to an example embodiment. 
         FIG. 2  is cross-section of an extension for the roller according to an example embodiment. 
         FIG. 3  is a perspective view showing the extension extending beyond the outer tube according to an example embodiment. 
         FIG. 4  is a perspective view showing the extension aligned flush with the outer tube according to an example embodiment. 
         FIG. 5  is a perspective view of a fully assembled roller shade system according to an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The description hereinafter describes exemplary embodiments of a telescoping, cut-to-size roller shade system in conjunction with the accompanying figures. Where possible, like numerals are used to denote like components. 
     Referring to  FIGS. 1-5 , the roller shade system, generally designated by reference number  1 , includes a hollow, tubular roller  10  that extends for the majority of the length of the shade. A generally tubular extension  20  is telescopically inserted into one end of the roller  10  to extend the length of the roller  10  to match the length of the shade. The portion of the extension  20  that extends beyond the roller  10  is surrounded by an outer tube  30 , which may be fixed or rotatable relative to the extension  20 . The extension  20  acts to provide strength and stability to the outer tube  30 . The diameter of the outer tube  30  and the roller  10  are approximately the same, thereby providing a continuous single-diameter contour along the length of the shade. A fabric shade  40  is wrapped around the fully assembled roller assembly. 
       FIG. 2  is a cross-sectional view of the extension according to an example embodiment. According to this embodiment, the extension  20  includes an outer wall  22  of a generally uniform thickness and a plurality of winged splines  24  located around the outer circumference. The splines  24  can extend substantially along the entire length of the extension  20 , but may also extend along only a portion thereof. Each spline  24  comprises first and second members  26 ,  27  splayed outward from a common center point  25  on the outer wall  22 . 
     The first and second members  26 ,  27  are designed to be resiliently flexible, which provides for a tight frictional fit that resists lengthwise movement and relative rotation between the extension  20  and the roller  10 , while still allowing the extension  20  to slide lengthwise within the roller  10  when under deliberate, intentionally-applied compressive forces. The flexibility of the first and second members  26 ,  27  also allows the extension  20  to be inserted into rollers  10  of varying diameters. Factors contributing to the flexibility of the first and second members  26 ,  27  may include the type of material used, the thickness, and the curved contour of the members. 
     The roller  10  may be formed from a sturdy, rigid material, such as plastic, metal or the like. The extension  20  may be formed from a sturdy material, such as plastic, an elastomer, metal or the like. For example, the extension  20  may be an extruded tube of chlorinated polyvinyl chloride (CPVC) type thermoplastic, UL rated 94VO so as to provide sufficient structural rigidity for the outer wall  22  and flexibility for the splines  24 . The outer tube  30  may be formed from cardboard, plastic, an elastomer, sheet metal or the like. For example, the outer tube  30  may be made of a thin layer of cardboard or plastic for reasons of economy, ease of manufacturing, and ease of cutting to adjust to the appropriate length. 
     To adjust the length of the roller shade assembly, the outer tube  30  is measured to the necessary length and then placed in a window shade cutter, such as manufactured by Star Shade Cutter Co. Typically, the cutting blade of the shade cutter is fixed and the outer tube  30  is rotated such that the cutting blade moves around the outer tube  30 . It is intended that the cutting blade slices off only the excess portion of the outer tube  30 , and not the extension  20 . The cutting blade may inadvertently make initial contact with the outer tips of the first and second members  26 ,  27  of the splines  24 , yet given the structure of the extension  20 , the splines  24  will act as a warning to the operator to stop the cutting operation. This allows the structural integrity and rigidity of the extension  20  to remain uncompromised after the cutting operation is complete. The extension  20  is preferably made from a softer material such as plastic or an elastomer, which will reduce or prevent damage from occurring to the cutting blade when cuts through the thin outer tube  30  and comes in contact with the more substantial extension  20 . 
     After the outer tube  30  is cut to the appropriate length, a portion of the extension  20  will be left extending beyond the end of the outer tube such as shown in  FIG. 3 . The extension  20  can be slid further into the roller  10  until the end of the extension  20  is flush with the end of the outer tube  30  such as shown in  FIG. 4 . The fabric shade  40  is wrapped around the fully assembled roller shade assembly as shown in  FIG. 5 . 
     A clutch  32  and/or idler  34  may be inserted directly into the hollow cavities of the roller  10  and extension  20 , respectively, in which case the inner surface defining the hollow cavities may be keyed to for rotational engagement with the clutch or idler such as shown in  FIG. 1 . A pin-bearing end cap  36  may alternatively be inserted into the hollow cavity at the exposed ends of the extension  20  in order to engage the roller shade assembly directly with a bracket that is used for mounting such as shown in  FIG. 5 . 
     Now that exemplary embodiments of the present invention have been shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present invention is to be construed broadly and limited only by the appended claims, and not by the foregoing specification.