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: 
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a shade cloth for a Roman shade and more particularly, to a width-adjustable shade cloth for a Roman shade. The invention relates also to a Roman shade using a retractable headrail and the width-adjustable shade cloth.  
         [0003]     2. Description of the Related Art  
         [0004]     Roman shade manufacturers provide limited sizes of Roman shades for selection. When purchasing a Roman shade, the user can only select the size that is slightly greater than the width (transverse length) of the window, and then use a cutting tool to cut one lateral side of the Roman shade subject to the size of the window, and then install the well-cut Roman shade in the window. This installation procedure is workable. However, the user must measure the size of the window before selecting the desired Roman shade. After selection of the desired Roman shade, the user must cut the Roman shade to fit the size of the window. If the selected Roman shade is improperly cut, a secondary cutting procedure may be needed. If the Roman shade is cut too far, the Roman shade become unable to shade the whole area of the window, and the user shall share the loss. Further, the distributor or sales center shall provide a cutting machine for the consumers to cut selected Roman shades. The installation of such a cutting machine is expensive. Training of workers to use the cutting machine greatly increases the labor cost. The distributor or sales center shall bear the loss of a defective Roman shade due to an improper cut by a worker of the distributor or sales center.  
       SUMMARY OF THE INVENTION  
       [0005]     It is the primary objective of the present invention to provide a shade cloth for a Roman shade, which has the lateral side thereof inwardly fordable so that the user can conveniently adjust the width (transverse length) of the shade cloth to fit different sizes of windows.  
         [0006]     To achieve this objective of the present invention, the shade cloth for a Roman shade comprises a cloth body having a front side, a back side and two opposite lateral side edges, and a coupling unit provided at the back side of the cloth body adjacent to one of the two opposite lateral side edges for securing the respective one of the two opposite lateral side edges to the back side of the cloth body so as to adjust transverse length of the cloth body.  
         [0007]     It is another objective of the present invention to provide a width-adjustable Roman shade that can conveniently be adjusted to fit different sizes of windows. The Roman shade provided by the present invention comprises a retractable headrail and the above-mentioned shade cloth connected to and suspended from the headrail.  
         [0008]     In a preferred embodiment of the present invention, the coupling unit is formed of a male snap element and a plurality of female snap elements transversely aligned with the male snap element and connectable to the male snap element.  
         [0009]     In another preferred embodiment of the present invention, the coupling unit comprises a first coupling element and a second coupling element that is aligned transversely with the first coupling element and is connectable to the first coupling element. Preferably, the first coupling element and the second coupling element are respectively hook and loop tapes of a hook and loop fastener. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a front view of a width-adjustable Roman shade according to a first preferred embodiment of the present invention.  
         [0011]      FIG. 2  is a rear side view of the width-adjustable Roman shade according to the first preferred embodiment of the present invention.  
         [0012]      FIG. 3  is a sectional view taken along line  3 - 3  of  FIG. 1 , showing the locking device locked the second headrail element to the first headrail element of the retractable headrail.  
         [0013]      FIG. 4  is an enlarged view of a part of  FIG. 1  showing the method of connection of the shade body to the headrail.  
         [0014]      FIG. 5  is an exploded view of a support rod for the width-adjustable Roman shade according to the first preferred embodiment of the present invention.  
         [0015]      FIG. 6  is a schematic front view of the first preferred embodiment of the present invention, showing an adjustment status of the width-adjustable Roman shade.  
         [0016]      FIG. 7  is a front view of a width-adjustable Roman shade according to a second preferred embodiment of the present invention.  
         [0017]      FIG. 8  is a rear side view of the width-adjustable Roman shade according to the second preferred embodiment of the present invention.  
         [0018]      FIG. 9  is a front view of a width-adjustable Roman shade according to a third preferred embodiment of the present invention.  
         [0019]      FIG. 10  is a rear side view of the width-adjustable Roman shade according to the third preferred embodiment of the present invention.  
         [0020]      FIG. 11  is an elevational view of a support rod for the width-adjustable Roman shade according to the third preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]     Referring to  FIGS. 1-6 , a width-adjustable Roman shade  10  in accordance with the first preferred embodiment of the present invention is shown comprising a retractable headrail  11 , a shade cloth  12 , a plurality of support rods  13 , two lift cords  14 , a plurality of coupling units  15 , and a fastening unit  16 .  
         [0022]     The headrail  11  is installed in the top side of the window (not shown). The fabric shade cloth  12  comprises a cloth body  121  fixedly fastened to the bottom side of the headrail  11 , a plurality of elongated pockets  122  transversely provided at the back side of the cloth body  121  at different elevations (according to this embodiment, the number of the pockets  122  is 7), and a plurality of cord-guiding loops  123  respectively provided at the pockets  122  on the outside and arranged into two vertical lines. The support rods  13  are respectively inserted into the pockets  122  to support the cloth body  121  transversely (horizontally) in shape. The lift cords  14  each have one end tied to the lowest one of one of the two vertical lines of the cord-guiding loops  123  and the other end inserted through the others of the respective vertical line of the cord-guiding loops  123  and then coupled to the headrail  11  for controlling lifting and lowering of the bottom side of the cloth body  121 .  
         [0023]     Referring to  FIG. 2  again, the coupling units  15  are transversely provided at the back side of the cloth body  121  at different elevations near one lateral side (according to this embodiment, the number of the coupling units  15  is 8 wherein one coupling units  15  is provided at the top side of the cloth body  121  and the other coupling unit units  15  are respectively provided corresponding to the pockets  122 ). Each coupling unit  15  is comprised of a male snap element  151  provided near one lateral side edge of the cloth body  121  and a plurality of female snap elements  152  transversely aligned with the male snap element  151  in a line. By means of turning one lateral side edge of the cloth body  121  backward to fasten the male snap element  151  of each coupling unit  15  to one respective female snap element  152 , the width (transverse length) of the shade cloth  12  is relatively adjusted.  
         [0024]     Referring to  FIGS. 3 and 4 , the headrail  11  comprises a first headrail element  111 , a second headrail element  112 , and a locking device  113 . The first headrail element  111  and the second headrail element  112  are narrow elongated elements. The first headrail element  111  has an internal contour fitting the external contour of the second headrail element  112  such that the second headrail element  112  is axially movable in and out of the first headrail element  111 . The locking device  113  according to this embodiment is a tightening up screw perpendicularly mounted in the peripheral wall of the first headrail element  111  and stoppable against the periphery of the second headrail element  112  to hold down the second headrail element  112  in position by means of friction resistance.  
         [0025]     The fastening unit  16 , as shown in  FIG. 4 , is comprised of a first fastener  161 , a second fastener  162 , and a third fastener  163 . The second fastener  162  and the third fastener  163  are connectable to the first fastener  161 , i.e., the first fastener  161  can be a male fastening member (or female fastening member) and the second fastener  162  and third fastener  163  can be female fastening members (or male fastening members) connectable to the first fastener  161 . Preferably, hook and loop tapes of a hook and loop fastener are used for the fasteners  161 - 163 , i.e., the first fastener  161  can be a hook tape of the hook and loop fastener (or loop tape of the hook and loop fastener), and the second and third fasteners  162 ,  163  can be loop tapes (or hook tapes). The first fastener  161  is provided at the front surface of the cloth body  121  and extended along the top side edge of the cloth body  121 . The second fastener  162  is provided at the back side of the first headrail element  112  and longitudinally (axially) extended along the length of the first headrail element  112 . The third fastener  163  is provided at the back side of the second headrail element  113  and longitudinally (axially) extended from one end (the outer end) of the second fastener  113  toward the other end (the inner end) of the second fastener  113  to a distance.  
         [0026]     Referring to  FIG. 5 , the support rods  13  are retractable rod members each comprised of a tubular outer rod element  131 , an inner rod element  132 , and an elastic socket member  133 . The elastic socket member  133  is provided at one end of the tubular outer rod element  131 . The inner rod element  132  is inserted through the elastic socket member  133  into the inside of the tubular outer rod element  131  and axially movable relative to the tubular outer rod element  131  to adjust the length of the respective support rod  13 . After each adjustment, the friction resistance between the elastic socket member  133  and the inner rod element  132  locks the respective support rod  13  to the adjusted length.  
         [0027]     When adjusting the width (transverse length) of the Roman shade  10 , extend or receive the rod members  13  to the desired length, and then unfasten the fastening unit  16  to detach the shade cloth  12  from the headrail  11 , and then turn the respective lateral side edge of the cloth body  121  backward to fasten the male snap elements  151  of the coupling units  15  to selected respective female snap elements  152  so as to adjust the width (transverse length) of the shade cloth  12 , and then adjust the length of the headrail  11  subject to the adjusted width (transverse length) of the shade cloth  12 , and then fasten the first fastener  161  to the second fastener  162  and third fastener  163  to secure the shade cloth  12  to the headrail  11 , as shown in  FIG. 6 .  
         [0028]      FIGS. 7 and 8  show a width-adjustable Roman shade  20  constructed according to the second preferred embodiment of the present invention. The width-adjustable Roman shade  20  comprises a headrail  21  installed in the top side of the window (not shown), a shade cloth  22 , which comprises a cloth body  221 , an elongated pocket  222  transversely provided at the back side of the cloth body  221  and extended along the bottom side of the cloth body  221  and a plurality of cord-guiding loops  223  respectively provided at the back side of the cloth body  221  and arranged into two vertical lines, a support rod  23  inserted into the pocket  222  to support the cloth body  221  transversely (horizontally) in shape, two lift cords  24  each having one end tied to the lowest one of one of the two vertical lines of the cord-guiding loops  223  and the other end inserted through the others of the respective vertical line of the cord-guiding loops  223  and then coupled to the headrail  21  for controlling lifting and lowering of the bottom side of the cloth body  221 , and a plurality of coupling units  25  transversely provided at the back side of the cloth body  221  at different elevations near one lateral side.  
         [0029]     The headrail  21 , support rod  23  and lift cords  24  of this second embodiment are substantially similar to those of the aforesaid first embodiment. The main feature of this second embodiment is outlined hereinafter. As illustrated in  FIG. 8 , the coupling units  25  are formed of hook and loop fasteners, each comprised of a narrow short first coupling element  251 , e.g. a short hook tape of the hook and loop fastener, provided at the back side of the cloth body  221  near one lateral side edge of the cloth body  221  and a narrow long second coupling element  252 , e.g. a long loop tape of the hook and loop fastener, transversely provided at the back side of the cloth body  221  and aligned with the narrow short first coupling element  251  in a line. By means of turning one lateral side edge of the cloth body  221  backward to fasten the narrow short first coupling element  251  of each coupling unit  25  to the respective narrow long second coupling element  252 , the width (transverse length) of the shade cloth  22  is relatively adjusted.  
         [0030]      FIGS. 9-11  show a width-adjustable Roman shade  30  constructed according to the third preferred embodiment of the present invention. The width-adjustable Roman shade  30  comprises a headrail  31  installed in the top side of the window (not shown), a shade cloth  32 , which comprises a cloth body  321 , a plurality of elongated pockets  322  transversely provided at the back side of the cloth body  321  at different elevations, and a plurality of cord-guiding loops  323  respectively provided at the pockets  322  on the outside and arranged into two vertical lines, a plurality of support rods  33  respectively inserted into the pockets  322  to support the cloth body  321  transversely (horizontally) in shape, two lift cords  34  each having one end tied to the lowest one of one of the two vertical lines of the cord-guiding loops  323  and the other end inserted through the others of the respective vertical line of the cord-guiding loops  323  and then coupled to the headrail  31  for controlling lifting and lowering of the bottom side of the cloth body  321 , and a plurality of coupling units  35 .  
         [0031]     The support rods  33  and lift cords  34  of this third embodiment are substantially similar to those of the aforesaid first embodiment. The main feature of this third embodiment is outlined hereinafter. As shown in  FIG. 9 , the headrail  31  comprises a first headrail element  311 , two second headrail elements  312 , and two locking devices  313 . The first headrail element  311  and the second headrail elements  312  are narrow elongated elements. The first headrail element  311  has an internal contour fitting the external contour of the second headrail elements  312  such that the second headrail elements  312  are axially movable in and out of the two distal ends of the first headrail element  311 . The locking devices  313  according to this embodiment each are a tightening up screw perpendicularly mounted in the peripheral wall of the first headrail element  311  and stoppable against the periphery of the second headrail elements  312  respectively to hold down the second headrail elements  312  in position by means of friction resistance.  
         [0032]     As shown in  FIG. 10 , the coupling units  35  are arranged into two symmetrical sets and symmetrically transversely provided at the back side of the cloth body  321  at different elevations near the two opposite lateral sides of the cloth body  321 . Each coupling unit  35  is comprised of a male snap element  351  provided near one lateral side edge of the cloth body  321  and a plurality of female snap elements  352  transversely aligned with the male snap element  351  in a line. By means of turning one lateral side edge of the cloth body  321  backward to fasten the male snap element  351  of each coupling unit  35  to one respective female snap element  352 , the width (transverse length) of the shade cloth  32  is relatively adjusted.  
         [0033]     As shown in  FIG. 11 , the support rods  33  are wooden or plastic rod members each having a plurality of parallel grooves  331  extended around the periphery and symmetrically disposed near the two distal ends. When adjusting the width (transverse length) of the width-adjustable Roman shade  30 , the user can break each support rod  33  at one groove  331 .  
         [0034]     Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.

Summary:
A shade cloth for use in a Roman shade includes a cloth body and a plurality of coupling units provided at a back side of the cloth body at different elevations adjacent to one lateral side edge of the cloth body for securing the respective lateral side edge of the cloth body to the back side of the cloth body so as to adjust the transverse length of the cloth body. The present invention relates also to a Roman shade having a retractable headrail and the shade cloth connected to and suspended from the headrail.