Patent Publication Number: US-7708047-B2

Title: Cellular coverings for roll-up shades

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is a divisional of U.S. application Ser. No. 11/012,583 filed Dec. 14, 2004, which application claims the benefit of U.S. provisional application No. 60/531,360 filed Dec. 19, 2003. The &#39;583 application and the &#39;360 application are incorporated by reference into the present application in their entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to coverings for architectural openings, and more specifically to a roll-up shade having a cellular structure. 
   2. Description of the Relevant Art 
   Window shades composed of multiple layers of fabric arranged to create pockets of still air in their structure are commonly described as cellular shades. Cellular shades are desirable for their ability to not only help insulate an opening, such as a window, but also their pleasing aesthetic appearance. 
   Some cellular type shades have been of the accordion variety, wherein the cells are collapsed onto one another as a foot rail is raised to create a compact stack. This type of cellular shade typically requires lift cords that are threaded through the interior of the cells. 
   Conversely, typical roller shades do not utilize lift cords but rather, retraction is accomplished by simply rolling the shade material onto a roller. Fabrication of a roller shade is relatively inexpensive typically comprising cutting the shade material to size, attaching a roller and foot rail to the material and attaching the roller to a head rail. Roller shades are typically fabricated using flat covering materials that comprise one or more plies of fabric. 
   Several roll-up cellular shades have been devised that combine cellular coverings with the convenience and lower cost of the roll-up shade. One type of roll-up cellular covering is described by Thomas P. Hopper in U.S. Pat. Nos. 4,194,550, and 4,039,019. The roll-up shade coverings described in the Hopper patents comprise two essentially flat sheets that are separated by and held apart by a variety of devices that collapse as the coverings are rolled up. The Hopper shades are designed to maximize the insulating capabilities of the coverings, but because of the flat front and back sheets, the shades tend to lack the aesthetic appeal of more traditional cellular shades. U.S. Pat. No. 5,547,006 is an illustration of a shade which is arguably more aesthetically pleasing than the Hopper shades, resembling a conventional roman shade. 
   SUMMARY OF THE INVENTION 
   The present invention concerns various arrangements of cellular covering materials and roll-up type shade assemblies in which the materials are incorporated. 
   In some arrangements, a cellular shade covering comprises a back sheet of fabric and a plurality of generally parallel longitudinally-extending cells suspended from and spaced on the back sheet. Each cell includes a longitudinally extending strip of fabric. Each strip of fabric is formed to include a longitudinally-extending top edge and, a longitudinally-extending bottom edge, wherein the strip is attached to the back sheet at locations generally proximate both the top and bottom edge. The portion of the strip between the top and bottom edges extends away from the back sheet to form a cell. 
   In other arrangements, the cellular covering comprises a plurality of longitudinally-extending fabric strips. Each strip has longitudinally-extending top and bottom edges forming a longitudinally-extending cell with a top end and a bottom end, and wherein each strip is secured to the above adjacent cell proximate the top edge. 
   In still other arrangements, the cellular covering comprises a back sheet, and a plurality of generally parallel longitudinally-extending cells. Each cell of the plurality includes a longitudinally-extending strip of fabric having a longitudinally-extending top edge and a longitudinally-extending bottom edge. The longitudinally-extending strip of each cell is attached to the back sheet proximate the bottom edge at a first location. Further, the longitudinally-extending strip is also attached along its top edge to another longitudinally-extending strip of an above adjacent cell at a second location that is generally proximate the bottom edge of the above adjacent longitudinally extending strip. 
   In further arrangements, a cellular shade comprises a plurality of longitudinally-extending fabric cells. The cells are vertically spaced apart from each other and separated by an intervening vertically-extending fabric spacing section. Further, the cells are adapted to collapse when wound onto a roller of a roll-up type shade assembly and expand when the covering is unwound from the roller and extended. 
   Other aspects, features and details of the present invention can be more completely understood by reference to the following detailed description of a preferred embodiment, taken in conjunction with the drawings and from the appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an isometric front view of a typical cellular roll-up shade according to one embodiment of the present invention. 
       FIG. 2  is a fragmentary side view of a roll-up shade with a cellular covering according to a first embodiment of the invention. 
       FIG. 3  is a fragmentary side view of a roll-up shade with a cellular covering according to a second embodiment of the invention. 
       FIG. 4  is a fragmentary side view of a roll-up shade with a cellular covering according to a third embodiment of the invention. 
       FIG. 5  is a fragmentary side view of a roll-up shade with a cellular covering according to a fourth embodiment of the invention. 
       FIG. 6  is a fragmentary side view of a roll-up shade with a cellular covering according to a fifth embodiment of the invention. 
       FIG. 7  is a fragmentary side view of a roll-up shade with a cellular covering according to a sixth embodiment of the invention. 
       FIG. 8  is a fragmentary side view of a roll-up shade with a cellular covering according to a seventh embodiment of the invention. 
       FIG. 9  is a fragmentary side view of a roll-up shade with a cellular covering according to an eighth embodiment of the invention. 
       FIG. 10  is a fragmentary side view of a roll-up shade with a cellular covering according to a ninth embodiment of the invention. 
       FIG. 11  is a fragmentary side view of a roll-up shade with a cellular covering according to a tenth embodiment of the invention. 
       FIG. 12  is a fragmentary side view of a roll-up shade with a cellular covering according to an eleventh embodiment of the invention. 
       FIG. 13  is a fragmentary side view of a roll-up shade with a cellular covering according to a twelfth embodiment of the invention. 
       FIG. 14  is a fragmentary side view of a roll-up shade with a cellular covering according to a thirteenth embodiment of the invention. 
       FIG. 15  is a fragmentary side view of a roll-up shade with a cellular covering according to a fourteenth embodiment of the invention. 
       FIG. 16  is a fragmentary side view of a roll-up shade with a cellular covering according to a fifteenth embodiment of the invention. 
       FIG. 17  is an end view of a strip of fabric with a hem at one end for use in forming a cell of a cellular covering. 
       FIG. 18  is a side view illustrating a strip of fabric positioned in a hinged platen for use in forming a cell of a cellular covering. 
       FIG. 19  is a side view showing the hinged platen of  FIG. 17  closed with the strip of fabric therein to form the cell. 
       FIG. 20  is a transverse section taken through a strip of material used in making a cell for a sixteenth embodiment of the present invention. 
       FIG. 21  is a transverse section similar to  FIG. 20  with the strip having been initially folded. 
       FIG. 22  is a transverse section similar to  FIGS. 20 and 21  with the strip finally folded into a cellular configuration. 
       FIG. 23  is a transverse section of two interconnected cells of the type shown in  FIG. 22  in a partially inflated condition. 
       FIG. 24  is a transverse section similar to  FIG. 23  showing the cells fully inflated. 
       FIG. 25  is a transverse section similar to  FIG. 24  with a plurality of interconnected cells suspended from a take-up roller. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Various embodiments of cellular coverings for use with roll-up type shade assemblies are described. Each embodiment of the present invention includes a plurality of configurational elements for encouraging the cells of the coverings to expand (“inflate”) when an associated covering is unrolled from a roller or extended to cover an architectural opening. 
   Throughout the description, the word “fabric” is used to describe the primary material comprising a cellular covering. It is to be appreciated that various types of suitable flexible sheets of materials can be used with the cellular coverings described herein. Suitable flexible sheet materials include fabrics, films, foils, flexible laminated sheets, and the like. Also, a sheet, as the term is used herein unless otherwise specifically stated, comprises either a single unitary piece or a plurality of strips or other shaped pieces that are adhesively or otherwise joined together to form a single piece that is thin in comparison to its length and breadth. Further, as described herein, adhesive seams are specified for joining the various pieces of fabric that form the cellular roll-up coverings together. While it is appreciated that the preferred embodiments utilize an adhesive material, other materials and/or manners of joining the various pieces of fabric together can be utilized. For instance, the adhesive seams could be replaced with sewn seams or could be ultrasonically welded. Alternatively, rivets or other types of mechanical fasteners could be used. Additionally, when a thermoplastic film or fabric material is utilized, the various strips and pieces could be fused together. Accordingly, as used herein, references to adhesives and adhesive seams are intended to cover all suitable manners of joining the associated pieces of fabric together. 
     FIG. 1  is an illustration of a typical cellular roll-up shade assembly according to the invention. The assembly  100  includes a roller  105  that is rotatably mounted at either end to mounting brackets  110 . The mounting brackets are utilized to secure the assembly to a surface such as a wall or a casement that surrounds an architectural opening. The brackets  110  may also include features for attaching a housing  115  to the brackets. A typical housing is closed on the front side of the shade assembly and the sides thereof to hide the roller from view. A covering  120  is attached to the longitudinally-extending outside surface of the roller along the covering&#39;s generally horizontally-extending top. The covering includes one or more cells  125  of varying configurations as are described in detail below. A horizontally-extending bottom end of the covering that is opposite the top end may be attached to a foot rail  130  in selected embodiments. The foot rail  130  is generally weighted to help pull the covering downwardly as the covering is unwound from the roller. Additionally, the weight of the foot rail can help to cause the cells to “inflate” (open) as the covering  120  is deployed. Certain embodiments may not utilize a foot rail. Other embodiments may conceal a weight(s) or a dowel in a loop of covering material proximate the covering&#39;s bottom end. 
   The typical cellular roll-up shade assembly  100  also includes a retraction mechanism (not shown) adapted to retract the covering  120  by rolling the covering onto the roller  105 . Retraction mechanisms for roll-up shades are well known in the art. One type of retraction mechanism comprises a spring that biases the roller relative to the mounting brackets  110  to rotate in either a clockwise or counterclockwise direction. The spring-type retraction mechanism also includes a locking device that counteracts the spring bias and holds the covering in an extended position. A user must release the locking mechanism to retract the shade. In a typical roll-up shade, the locking mechanism is released by pulling downwardly on the covering for a short distance. Some spring-type retraction mechanisms may also include a dampening device to brake and slow the rate of retraction of the covering. It is to be appreciated that other types of retraction devices or no retraction device can be utilized with the invention. For instance, a motorized retraction/extension device could be used with or without an associated remote control system to raise and lower the covering. 
   One of the primary considerations concerning the configuration of the cellular covering for use in roll-up shade assemblies is the tendency of the cells on the covering to open or inflate when the shade is unrolled. At least three configurational aspects of the cells of the present invention encourage inflation: 
   (1) the fabric “set” attributable at least partially to the curvature of the roller; 
   (2) the difference between the length of a front fabric portion between the top and bottom seams of a cell and the rear fabric portion between the same seams; and 
   (3) the folds, bends or creases created in the fabric of the cells that when unrolled tend to cause the fabric of the cell to spring into a preferred set. Certain embodiments utilize additional configurational aspects to further promote inflation including: (1) configuring the cells to create a leverage effect; and (2) attaching the front portion of a top cell of a covering to one location on the roller and attaching a back portion of a cell at the top end of the covering to a second location on the roller circumferentially spaced from the first. Further, configurational aspects for amplifying the inflation of cells as described in U.S. Pat. No. 5,547,006, which is hereby incorporated by referencing its entirety, can be utilized with the coverings of the present invention. 
   Each cell  125  incorporated in the various covering embodiments of the present invention utilizes at least two folds within the fabric to help inflate and open the cell as it is unwound from the roller. When a covering is rolled up on the roller, the cell fabric at each fold typically folds over onto itself creating approximately a 180 degree bend. However, fabrics in general (and certain films, foils and laminates) are generally resistant to taking a sharp set and upon unrolling from the roller, the fabric unfolds at least partially, causing the associated cell to open. 
   Two types of folds are utilized in the embodiments described herein. The first type of fold is typically formed as a result of the configuration of the fabric comprising a cell that has not been given a permanent set by either (i) applying heat to a crease while the fabric is being restrained in the preferred position or (ii) running the fabric at the desired fold location through a creasing device. The second type of fold is that having a permanent set, wherein the fold is set to a specified degree of bend less than 180 degrees. With either type of fold, when the fold is unrolled from the roller, it will be encouraged to spring back to a degree of fold of less than a 180 degree bend, effectively pulling the associated portion of a cells fabric with it to inflate the cell. 
   A first embodiment of the present invention is illustrated in  FIG. 2  and shows two cells  205  of a plurality of cells that comprise a cellular covering  200 . Each cell  205  is box-shaped and formed from a strip of fabric  210  that includes a plurality of generally horizontally extending folds  215 - 230 . Each strip comprising the covering  200  extends downwardly from a top edge  235  to a first fold  215  to form the back side  238  of the cell. From there, the strip extends forwardly to form the bottom side  240  of the cell. The strip forms a second fold  220  at the front edge of the bottom side. From the second fold, the strip extends generally upwardly to form the front side  242  of the cell. A third fold  225  is formed at the top edge of the front side. From the third fold, the strip extends rearwardly until it comes into contact with the back side  238  forming the top side  252  of the cell. At the junction with the back side, a fourth fold  230  is formed from which the strip then extends downwardly along the front surface of the back side for a short distance before terminating in a bottom edge  245 . Between the bottom edge and the fourth fold, the terminal portion  250  of the strip is adhesively joined to the back side  238  at adhesive seams  255 . 
   The back side  238  of each strip extends upwardly above the top side of the cell. Proximate the top edge of the topmost cell  205 , the back side is attached with the roller  105 . The top edge of each other cell of the plurality of cells including the lower cell  205  shown in  FIG. 2  are joined to the back surface of the back side of the cell immediately adjacent and above the top edge by an adhesive seam  258 . The resultant covering comprises a plurality of cells separated by spacing sections  260  and  260 ′, typically comprising a single thickness of fabric, to provide an aesthetically pleasing product that can be easily retracted and extended from a roller of a roll-up shade assembly. 
   Referring to  FIG. 2  and the first embodiment covering, when a cell  205  is rolled up onto the roller and a successive layer of the covering is wrapped over the cell, the top, bottom and front sides of the associated fabric strip  220  nest compactly against the back sheet with the strip folding to approximately 180 degree bends at folds  220  and  230 . During extension or the unrolling of the covering from the roller, the tendency of the 180 degree bends at folds  220  and  230  to resiliently move back into a lower stress state having a lower bend angle, results in the opening or inflation of the cells. 
   A second embodiment of the covering in accordance with the present invention is shown in  FIG. 3 . In this embodiment, the back sides  338  of the cells  305  and the spacing sections  360  between adjacent cells are comprised of a fabric sheet  365  separate from the top, bottom and front sides of the cells. By utilizing a separate fabric sheet for the back sides  338  and spacing sections  360 , different fabric colors can be utilized resulting in a covering that when viewed from the front alternates between cells  305  of one color and spacing sections  360  of another color resulting in a covering  300  with an aesthetically pleasing striped appearance. 
   Further, as specifically illustrated in  FIG. 3 , the fabric sheet  365  comprising the back side  338  and spacing sections  360  can also be comprised of a plurality of fabric strips adhesively joined along adhesive seams  370 . It is appreciated that these strips could be the same type of material or differing types of material of differing colors if desired. Additionally, since each cell is made of a different strip of fabric, each cell could be of a different color. 
   The construction of a typical second embodiment cell will now be described in reference to  FIG. 3 . A generally horizontally-extending first fold  330  is formed a short distance from the top edge  335  of the fabric strip  310  comprising the top, front and bottom sides of the cell. The section of fabric between the top edge  335  and the first fold  330  is adhesively bonded to the front surface of the fabric sheet  365  comprising the back side  338  of the cell along a generally horizontally-extending adhesive seam  355 . From the first fold, the fabric strip  310  extends outwardly to form the top side  352  of the cell. The top side of the cell terminates at a second fold  325  and the fabric strip extends downwardly to form the generally vertical front side  342  of the cell. The front side terminates at a third fold  320  and the fabric strip continues inwardly to a fourth fold  315  to form the bottom side  340  of the cell. From the fourth fold, the strip  310  extends upwardly for a short distance and ends at a bottom edge  345  of the fabric strip. Between the bottom edge and the fourth fold, the cell is adhesively joined to the back side fabric sheet  365  by a generally horizontally-extending adhesive seam  355 . 
   In a manner similar to the first embodiment, the cells of the second embodiment fold flat against the back side fabric sheet forming 180 degree bends at folds one and three. During the unrolling or extension of the covering from the roller, the cells inflate due to the unfolding and resiliency at folds one and three. 
   Referring to  FIG. 4 , a third embodiment is very similar to the second embodiment except the fabric strip  310 ′ forming the cell  305 ′ extends downwardly instead of upwardly from the equivalent of the fourth fold  315 ′. Accordingly, when the cell is collapsed onto the roller three 180 degree bends are created providing additional cell expansion force due to the third 180 degree bend at the fourth fold  315 ′. As shown in the third embodiment, the shade comprises a single fabric back sheet  365 ′, but as with the second embodiment ( FIG. 3 ), the back sheet can be fabricated from more than a single strip. 
   The inflation of the first three embodiments are highly influenced by the type of fabric utilized to construct the cells. Stiffer fabrics that are also more resistant to creasing or taking a permanent set at ambient use conditions tend to create fuller and better defined cells. The spacing between the cells lacks the insulating value of the cells, but the visual emphasis of the cells&#39; shape is accentuated by the spacing which provides a unique and pleasing aesthetic appearance. 
   Embodiments four, five and six provide for cells that extend continuously over the surface of the covering providing for good insulating characteristics when compared to roll-up coverings without cells or with spaced cells. Further, the expanded cells provide an aesthetically superior look when compared to non-cellular roll-up shade coverings. 
   Referring to  FIG. 5 , the fourth embodiment cellular shade can be viewed as a variation on the second embodiment where the portion of the fabric strip  410  of a cell  405  that extends downwardly before terminating in a bottom edge  445  is secured typically along an adhesive seam  455  to an adjacent lower cell  405  instead of the back side fabric sheet  465 . In this manner, the connection of the bottom edge of a cell to the next lower cell is at a location that is transversely removed from the back sheet when considering the transverse dimension of a strip  410  as extending from a top edge of the strip to a bottom edge or vice versa. By using this type of attachment, the inflation of each cell is amplified and further encouraged into an open position not just by the folds in the cell  405  itself but by the inflation or opening of the adjacent lower cell  405 . Cells of this type of configuration can be made into a wide variety of configurations by varying the size of the fabric strips that comprise the cells. For instance, the thickness of the cell when inflated is largely a function of the transverse distance between the location of the adhesive seam  455  on the front or top side of the cell and the cell&#39;s location of attachment to the back sheet  465  proximate its first fold  430 . Further, the degree of longitudinal curvature along the front side  442  of each cell is affected by both the stiffness of the fabric and the distance from the location of attachment of the above adjacent cell and the attachment location proximate with the below adjacent cell. As illustrated in  FIG. 5 , only two distinct folds  430  and  415  are shown. It is to be appreciated, however, that cells  405  having additionally more distinct or set-creased fold lines are contemplated. 
     FIG. 5  is shown with the cells  405  of the covering facing outwardly as they are rolled onto the roller  105 . In a variation, the cells could face inwardly towards the roller. During the unrolling of this variation, the inflation contribution attributable to the fabric “set” from the curvature of the roller would be lost. 
   Referring to  FIG. 6 , a fifth embodiment of the invention is presented. The fifth embodiment is generally similar to the fourth embodiment except the top edges  535  and  570  of the topmost cell&#39;s fabric strip  510  and the back sheet  565  are each mounted to the roller  105  along circumferentially-spaced longitudinal lines of attachment. This spaced configuration causes the topmost cell to pull the front faces of the lower cells open when the covering is fully extended. 
   Additionally as illustrated in  FIG. 6 , the configuration of the fabric strips  510  that help form each cell differs from the fourth embodiment. The top edge  545  of each fabric strip  510  (except the strip for the topmost cell) is attached to the above adjacent cell  505  at a location proximate both the first fold  530  of the cell and the third fold  520  of the above adjacent cell  505 . The top side  552  of each cell also comprises the bottom side of the above adjacent cell. It is to be appreciated that one variation of the fifth embodiment can utilize a fabric strip construction that is essentially identical to that of the fourth embodiment. 
   Referring to  FIG. 7 , the sixth embodiment is illustrated. The sixth embodiment differs from the fifth embodiment only in that the section  672  of the fabric strip  610  between the bottom most fold  615  and the bottom edge  645  of the fabric strip  610  extends upwardly instead of downwardly. Accordingly, when the covering is rolled up, the fabric strip at the location of the bottom most fold  615  lies flat. This cell structure results in a smaller roll size when compared to the fifth embodiment, but also typically results in thinner cells  605  depending on the characteristics of the fabric utilized. 
   Embodiments seven through fifteen are cellular coverings wherein the cells face the roller  105  upon retraction. Additionally, these coverings include vertical spacing sections between each cell similar to embodiments one through three. Unlike the preceding embodiments, however, these embodiments utilize a lever arm effect to pull the cells open upon being unrolled from the roller. Referring generally to  FIG. 8  and the seventh embodiment, the weight of the cells and/or foot rail below a cell  705  being unrolled from a roller  105  create a tension force in the back side  738  of the cell which pulls down on a lever arm  775  formed at the top side  752  of the cell. The lever arm pivots about an adhesive seam  755  with an upwardly extending spacing section  760 , causing the front edge of the lever and the front side  742  of the cell to be opened or inflated. 
   Still referring to  FIG. 8 , each cell is typically comprised of a strip of fabric material  710 . The top edge  735  of the fabric strip is adhesively secured to the bottom corner of the above adjacent cell along the backside thereof proximate the fourth bend  715  of the above adjacent cell (except for the topmost cell in which the fabric strip is secured to the roller). The strip  710  extends downwardly from its top edge forming a spacer section  760 . The spacer section terminates at a first fold  730  and the fabric strip continues extending forwardly to a second fold  725  forming a portion of the cell&#39;s top side  752  as well as the lever arm  775 . From the second fold, the strip extends generally vertically downwardly to form the front side  742  of the cell  705 . The front side of the cell terminates at the third fold  720  wherein the fabric strip extends rearwardly towards a fourth fold  715  to form the bottom side  740  of the cell. From the fourth fold, the fabric strip extends upwardly to a fifth fold  777 . From the fifth fold, the fabric strip extends forwardly passing underneath the first fold  730  and a portion of the strip between the first and second folds before terminating at the bottom edge  745  of the strip  710 . The portions of the fabric strip between the first fold and the second fold and between the fifth fold and the bottom edge collectively form the top side  752  of the cell, which is, therefore, laminated. These two portions are attached to each other along an adhesive seam  755  proximate the first fold, which is located laterally between the fifth and second folds. The adhesive seam forms a pivot point for the top side lever arm  775 . In order to transfer a portion of the tension force from the back side  738  to the front side  742 , the lever arm must be of sufficient stiffness to carry the load. Accordingly, a plastic strip  780 , such as a strip of polyester sheet, may be bonded to the bottom of the top side. In practice, the plastic strip can be relatively thin such as half the thickness of the fabric strip but still add sufficient stiffness to the lever arm. Additionally, depending on the type of fabric utilized, the doubling up of the fabric mat may create a top side of sufficient stiffness to act as the lever arm without a plastic strip. 
   The ratio of the length of the lever arm  775  on either side of the adhesive seam  755  is an important design variable. The shorter the lever portion to the left of the adhesive seam  755  is relative to the portion to the right of the adhesive seam  755 , the less force there will be available to pull the cell  705  open. However, the cells of the seventh embodiment like the cells of the other embodiments are also encouraged to open or inflate due to the effect of 180 degree folds. In this embodiment the resistance to bending of the third and fifth folds  720  and  777  also helps to open the cells during unrolling. Accordingly, because of the combined opening forces, a left lever arm as short as 0.625″ and possibly as short as 0.30″ can still be sufficient to provide the necessary force to open a cell. To facilitate easy retraction and roll-up of the seventh embodiment covering the angle between each lever arm  775  and the front side  742  of each cell suspended from the lever arm at the second fold  725  should be at least 90 degrees when the cell is fully inflated. 
   Referring to  FIG. 9 , an eighth embodiment is illustrated. The cells  805  of the eighth embodiment are constructed differently from those of the seventh embodiment but the mechanical forces acting on the structure to cause the cells to inflate are similar to those of the seventh embodiment. Of particular note with the eighth embodiment is that the surface of the fabric strip facing forwardly in the spacing section  860  is different from the surface of the fabric strip facing forwardly on the front side  842  of the cell. Accordingly, if a fabric strip  810  is used to make the covering that has surfaces of different colors, the resulting shade will have a horizontal striped look with the cells and the spacing sections being of different colors. 
   The strip of fabric that comprises a cell  805  in the eighth embodiment includes a bottom edge  845  and extends generally horizontally from the edge to a first fold  815 . This horizontal portion of the fabric strip is coextensive with and forms part of the top side  852  of the below adjacent cell  805 . From the first fold, the strip extends upwardly to form a spacing section  860  and the back side  838  of the cell. The back side terminates at the second fold  830  where the fabric strip extends generally horizontally forwardly to a third fold  825  to form the top side of the cell. From the third fold, the fabric strip extends generally vertically downwardly to a fourth fold  820  forming the front side  842  of the cell. From the fourth fold, the fabric strip extends horizontally rearwardly to a fifth fold  844 , forming the bottom side  840  of the cell. From the fifth fold, the fabric strip extends upwardly a short distance to a top edge  846  overlapping the back side  838 . The fabric strip proximate the fifth fold  844  is adhesively secured to the back side by an adhesive seam  858 . Like the seventh embodiment, a strip of plastic or metallic material  880  may be adhesively bonded to the bottom of the top side to create a lever arm  875  of satisfactory stiffness. 
   Referring to  FIG. 10 , the ninth embodiment is substantially similar to the seventh embodiment except the fabric strip of each cell is folded over onto itself at a sixth fold  982  to form a doubled up top side  952 . The doubled up top side adds additional stiffness to the top side lever arm  975  and depending on the type of fabric utilized, a plastic strip may become unnecessary. The variations of the ninth embodiment may only be suitable for a roll-up shade with a covering of a limited length since lever arms comprised of fabric alone in the topmost cells of the covering may not be able to withstand the weight of a longer covering hanging therefrom. 
     FIG. 11  illustrates the tenth embodiment which is another variation on the seventh embodiment. The cells of the tenth embodiment are constructed differently from those of the seventh embodiment but the mechanical forces acting on the structure to cause the cells to inflate are similar to those of the seventh embodiment. 
   The strip of fabric  1010  that comprises a cell  1005  in the ninth embodiment includes a top edge  1035  where the fabric strip is adhesively secured to the back side  1038  of the above adjacent cell. From the top edge the fabric strip extends generally vertically downwardly to a first fold  1030  forming a spacing section  1060 . From the first fold the strip extends rearwardly and generally horizontally to a second fold  1025  forming a portion of the cell&#39;s top side  1052  as well as the left portion of the top side lever arm  1075 . From the second fold, the strip extends generally vertically downwardly to form the back side  1038  of the cell. The back side of the cell terminates at the third fold  1020  wherein the fabric strip extends forwardly towards a fourth fold  1050  to form the bottom side  1040  of the cell. From the fourth fold, the fabric strip extends upwardly to a fifth fold  1077  forming the front side of the cell. From the fifth fold, the fabric strip extends rearwardly passing below the first fold and the portion of the strip between the first and second folds before being folded back upon itself at a sixth fold  1082  and adhesively secured to itself. The fabric strip terminates at a bottom edge  1045  proximate the fifth fold. 
     FIG. 12  illustrates the eleventh embodiment which is another variation on the tenth embodiment. The cells on the eleventh embodiment are similarly constructed from fabric strips as the cells of the tenth embodiment. The eleventh embodiment, however, includes additional fabric strips  1084 , each additional strip extending from a top end  1086  secured to an intermediate vertical location on the back of a spacing section  1060  to a bottom end  1088  secured to a location on the back side  1038  of a cell proximate the second fold  1025  of the cell. These additional strips act to limit the amount the lever arms  1075  may be pivoted. It is appreciated that the additional pivot limiting strips  1084  can be utilized with any of the embodiments utilizing a lever arm to assist in cell inflation. 
     FIG. 13  illustrates the twelfth embodiment which is another variation on the tenth embodiment. In this embodiment, the back sides  1138  of the cells and the spacing sections  1160  are formed from a separate piece of material from the other sides of the cells in a manner similar to that described above concerning the second embodiment. The rear strip or strips of fabric  1165  comprising the back side hang generally vertically from the roller  105  and may include two bends  1186  and  1188  proximate their connection to the top side  1152  of a cell; a first back strip bend  1186  at the location of the joint with the top side of the cell, and a second back strip bend  1188  to the rear of the first back strip bend. As shown in  FIG. 13 , the cellular shade comprises a plurality of rear strips that are joined together by adhesive seams  1170 , although in variations the back sides and spacing sections can comprise a single rear strip. 
   A separate cell fabric strip  1110  is utilized to form the top, front and bottom sides of each cell of the twelfth embodiment. Each cell strip extends rearwardly from a top edge  1135  to a first bend  1130  where the strip is folded over onto itself and extends forwardly to a second bend  1125 , thereby forming a doubled top side of the associated cell. From the second bend  1125 , the cell strip extends downwardly to a third bend  1120  to form the front side  1142 . As illustrated depending on the type of fabric utilized with the cell strip, an impression may be left on the front side of the cell from the curvature of the roller, thereby adding an additional aesthetic quality to the covering. From the third bend  1120  the cell strip extends rearwardly to a fourth bend  1115  whereas the cell strip extends upwardly a short distance adjacent the corresponding rear strip  1165 . The cell strip is secured to the rear strip through an adhesive seam  1155  proximate the fourth bend. 
     FIG. 14  illustrates a thirteenth embodiment. The thirteenth embodiment is a variation on the tenth embodiment incorporating a relatively stiff strip of plastic  1090  that is secured to the inside of the cell by an adhesive and spans the fourth bend  1020  thereof. The resiliency of the strip when flexed, while the associated covering is in its deployed position, acts to pull the front side  1042  of the cell  1005  taut and flat. This configuration has been found to be most useful with relatively large cells wherein the curvature set of the roller can be more pronounced. 
   Concerning any of the embodiments described herein, variations in the construction of the shapes described can be accomplished by altering dimensions and through the use of fabrics with greater or lesser resiliency stiffness and resistance to creasing. Additional seams can also be added to insert new fabric strips of a different material at any point in the coverings. In some cases such as the first embodiment shown in  FIG. 1 , the bottom edge of the covering may be attached to the roller, creating a minor variation in the shape of the covering&#39;s cells. 
   While attaching the bottom edges of the coverings to the rollers instead of the top edges will not work for the lever arm embodiments seven through thirteen ( FIGS. 8-12 ), the lever arm principles can be reversed as indicated in Embodiments fourteen and fifteen as shown in  FIGS. 15 and 16 . In these embodiments, the cells are deflected upwardly from the bottom side  1240  of the cells as a result of the tension on the cells. While the structure of the cells is substantially reversed, the overall appearance of the cells is not significantly different from those using a top side lever. 
   The fourteenth and fifteenth embodiments differ only in the manner in which the fabric cell strips  1210  are attached to the fabric rear strips proximate their top edge  1235 . In the fourteenth embodiment ( FIG. 15 ), the strip is folded downwardly proximate its attachment to the rear strip at its top edge. In the fifteenth embodiment ( FIG. 16 ), the strip is folded upwardly proximate its attachment to the rear strip at its top edge. Only the fourteenth embodiment is described in detail in the following paragraph since the fifteenth embodiment is substantially similar save for the aforementioned difference. 
   Referring to  FIG. 15 , a fabric rear strip  1265  extends rearwardly from its front edge  1292  until a first rear strip fold  1286  where it extends downwardly at  1260  from the bottom side  1240  of the above adjacent cell until a second rear strip fold  1288 . The rearwardly extending portion of the rear strip forms part of the bottom side  1240  and lever arm  1275  of the preceding cell. From the second fold, the strip extends forwardly for a short distance until terminating at its bottom edge  1294 . The forwardly extending portion forms both part of the bottom side and the lever arm of the corresponding cell. In the case of the topmost rear strip it is secured directly to the roller  105 , typically by an adhesive strip. 
   A fabric cell strip  1210  forms the top, front and bottom sides of each cell. The cell strip extends upwardly for a short distance from its top end  1235  to a first bend  1230 . Along this distance the cell strip is adhesively secured to the rear strip. From the first bend, the strip extends generally forwardly to a second bend  1225  to form the top side  1252  of the cell. As can be seen in  FIGS. 14 and 15 , the second bend may be gradual rather than sharp or creased. From the second bend, the cell strip extends generally downwardly to a third bend  1220  to form the front side  1242  of the cell. From the third bend, the cell strip extends rearwardly to a fourth bend  1215  forming the bottom surface  1240  of the bottom side. From the fourth bend, the cell fabric is folded back onto itself and extends forwardly until terminating at a bottom edge  1245  of the cell strip. The cell strip is secured to itself where it is folded back onto itself. 
   As discussed above, concerning other embodiments, the doubled-up cell strip in conjunction with the folded over portions of the rear strip cause the bottom side to be significantly stiffer than the other sides of the cell thereby effectively forming a lever arm  1275 . The rear strip  1265  that forms the back side of the cell is connected to the lever arm at an intermediate location where the lever arm can pivot about the connection location. The front edge of the lever arm is connected to the front side of the cell at the third bend  1220 , and the other edge of the lever arm is connected to the depending cells by the associated rear strip. In operation, the weight of the depending cells pulls the lever arm downwardly to the left of the pivot location causing the portion of the lever arm in front of the pivot location to rise upwardly inflating the cell. 
   A sixteenth embodiment of a covering in accordance with the present invention is illustrated in  FIGS. 20-25 . In this embodiment, a plurality of cells  1305  are interconnected with each cell and an adjacent spacing section being formed from a single strip  1310  of material. The strip of material as viewed in a substantially deflated cellular configuration in  FIG. 22  has a first end  1315  adjacent to the bottom wall  1317  of the cell with the strip extending straight upwardly to a first fold  1320  so as to define a rear wall  1322  of the cell. The first fold is a sharp fold approaching 180°. At the first fold, the strip is returned downwardly along an arcuate path to a curve  1324  so as to define the front wall  1326  of the cell between the first fold and the curve  1324 . At the curve  1324 , the strip extends rearwardly, passes through a second curve  1328  so as to extend upwardly and is connected at  1325  with adhesive or the like to the first end  1315  at a location spaced from a second end  1330  of the strip. The strip, between its second end  1330  and the connection at  1325  defines a spacing section  1332  which is folded downwardly at a fold  1334 . The second end  1330  has a bead of adhesive so that it can be connected to the rear wall of the next adjacent underlying cell to secure the next adjacent underlying cell to the front surface of the spacing section between the adjacent cells. 
   As will be appreciated, a plurality of elongated cells formed and interconnected in this manner form the overall covering and a weighted rail (not shown) may be provided at the bottom to encourage full extension of the covering. The uppermost cell in the covering is connected to a roller  1336  ( FIG. 25 ) on the rear side of the roller with a connector strip  1338  that is adhesively secured to the rear surface of the rear wall of the cell adjacent to its top end. The connector strip is also secured to the roller in any suitable manner such as with adhesive  1340 . 
   With reference to  FIG. 20 , the strip  1310  of material having the desired stiffness and resiliency is illustrated in transverse cross-section, it being appreciated that the strip is of a length corresponding to the width or breadth of the covering to be formed from a plurality of the cellular formed and interconnected strips. The rear face of the strip has an elongated bead of adhesive on its rear surface adjacent to the upper or second end  1330  and a bead of adhesive on its rear surface adjacent to the lower or first end  1315  thereof. A pair of creases are conventionally formed in the strip, one  1339  in the rear surface just below the upper end  1330  of the strip and the other  1340  just below a midpoint of the height of the strip on its front surface. In  FIG. 21 , the strip is seen to be folded along the crease  1340  so as to define a straight vertical segment that becomes the rear wall  1322  of a cell formed from the strip and a straight front segment which is ultimately curved and becomes the front wall  1326  and bottom wall  1317  of the cell as well as the spacing section  1332 . The strip is next folded along the crease  1339  adjacent to the second end  1330  of the strip as shown in  FIG. 22  and the front straight segment of the strip as shown in  FIG. 21  is curved along the bottom wall  1317  and is attached at  1325  to the end  1315  by the adhesive strip that was provided along the first end  1315  of the strip. As can be seen in  FIG. 22 , the strip then assumes the form of a cell  1305  having a sharp bend  1320  at the top that approaches 180° and a broader bottom wall  1317  that is curved with the spacing section  1332  being a straight depending segment that becomes almost coplanar with the rear wall  1322  of the cell when interconnected with underlying cells. 
     FIG. 23  shows a pair of interconnected cells  1305  before weight has been applied to the cells causing them to fully expand or inflate as seen in  FIG. 24 . Before the weight is applied, the connection of the first end  1315  of the strip to the location  1325  adjacent to the second end  1330  is shown positioned along the rear of the cell. However, when weight is applied to the bottom of the covering made from the interconnected cells, this location  1325  is leveraged forwardly into the position shown in  FIG. 24  which causes the cell to expand forwardly or inflate. It will therefore be appreciated that the degree of expansion can be regulated by the amount of weight carried at the bottom of the covering. 
   Several embodiments may be combined to create a covering that has cells on both its front and back sides. For instance, the cells of the fourth embodiment could be combined with the cells of the seventh embodiment. The spacing between the cells can be uniform or varied according to a desired pattern. Additionally, the sizes of the cells can be varied over a single covering. 
     FIGS. 17-19  illustrate various operations that may be utilized in manufacturing cellular coverings in accordance with the invention. While variations of the manufacturing apparatus will be required to produce the various cell shapes taught herein, each cell type is characterized by an aggregate front side, top side and bottom side that is longer than its back side, and each cell-type is adhesively bonded along both edges of the fabric strip that forms each cell. It is appreciated that some of the cell-types require additional adhesive seams, and as in several of the embodiments additional pieces of fabric and or plastic strips may be utilized. 
   The illustrated manufacturing operations and apparatus are for use with fabric strips  1410  that have lines of hot melt adhesive already applied thereto. Accordingly, the fabric strip and the adhesive are reheated during fabrication so that the fabric strip sections can be joined together. The fabric folds or seams are commonly made by pulling the fabric through a fixture, which causes the fold to be formed. Alternatively, a procedure, wherein the fabric strip is held against hinged platens via a vacuum and the platens are then folded together, may be used to crease the strip proximate the hinge. Accordingly, hem  1494  of  FIG. 17  may be made by any suitable method and apparatus. As discussed above, the hem  1494  may form part of a lever arm such as the one illustrated in  FIG. 10  for the ninth embodiment. 
   In certain embodiments there may also be an adhesive line  1495  on the outside of the hem as shown in  FIG. 18 . To form a vane cell, fabric of this configuration is laid on a hinged vacuum platen  1496 . The platen is then closed, as shown in  FIG. 19 , and the adhesive line  1495  is heated in any suitable manner to soften it. The adhesive is then permitted to cool, the platen is opened, and the completed cell is removed. The cell can then be bonded to other cells to form the roll up covering. It is to be appreciated that the manufacturing method described herein is merely an example and that many other manufacturing methods that would be obvious to one of ordinary skill in the art may be utilized to fabricate the cells and the roll-up covering. 
   Although the present invention has been described with a certain degree of particularity, it is understood the disclosure has been made by way of example, and changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.