Abstract:
A sling chair includes a back frame member having side rails held in substantially parallel relation by a pair of cross bar members. In one embodiment, the cross bar members are generally curved so as to extend away from the back faces of the side rails, forming a concave back structure which can receive a sling member and, eventually, a seated occupant. The cross bar members have a notch allowing for insertion of a flexible rod and sling loop and sling member after assembly of the cross bar members and side rails. Insertion of the flexible rod and sling loop does not require tools. The cross members are adapted to retain the sling member in secure fashion through upper and lower backrest assemblies, resulting in better support and more efficient assembly. This also facilitates separate provisioning of decorative features to improve the chair&#39;s aesthetic qualities.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional App. Ser. No. 61/232,233, filed Aug. 7, 2009 and is a continuation-in-part of prior application U.S. application Ser. No. 12/217,446, filed Jul. 3, 2008, now U.S. Pat. No. 7,731,291, which is a continuation-in-part of prior application U.S. application Ser. No. 11/193,779, filed Jul. 29, 2005, now U.S. Pat. No. 7,458,641. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to chair constructions, and more particularly relates to a chair construction employing a sling-type backrest which promotes chair stability, comfort and a variety of design alternatives. 
     BACKGROUND OF THE INVENTION 
     Various types of sling chairs have been known which provide a somewhat concave and/or giving backrest. Such chairs generally include a back portion and a seat portion, and may optionally include armrest portions. The back portion generally includes a back frame and a flexible yet supportive backrest made of fabric or other suitable material and mounted to the back frame. Different mechanisms have been employed for securing the backrest to the back frame, and these prior art mechanisms have suffered from several deficiencies. First, these prior art mechanisms often fail to provide a secure connection, which can result in the backrest being unsupportive of the seated individual. Second, sling chairs often expose aspects of the sling hardware, such as attachment elements or fasteners, and it would be aesthetically desirable to hide such aspects. Further, the sling backrest for these chairs is frequently retained along the chair side rail supports, creating side-to-side sling tension, restricting the potential to add decorative chair features, and complicating assembly. 
     SUMMARY OF THE INVENTION 
     The present invention provides a connection assembly for a sling chair which allows for efficient chair assembly and results in a comfortable yet sturdy chair. The present invention includes a back frame member having side rails held in substantially parallel relation by a pair of cross bar members. In one embodiment, the cross bar members are generally curved so as to extend away from the back faces of the side rails, forming a concave back structure which can receive a sling member and, eventually, a seated occupant. The cross bar members are adapted to retain the sling member in secure fashion through upper and lower backrest assemblies. In this way, the sling member is not secured to the side rails, but rather to the cross bar members, resulting in better support, a more secure connection and more efficient assembly. The method of securing the sling member using a detachable support bar having a scaffold support element ensures that the sling member is efficiently and securely retained. The present invention also facilitates separate provisioning of decorative features to improve the chair&#39;s aesthetic qualities. 
     Another aspect or embodiment is a back for a sling chair. A fabric sling back is used, the sling having a height and width to form an upper end and a lower end, a lateral pocket loop across the lower end of the sling with a loop diameter, with the loop defining at least one side pocket opening at one end. The back includes a pair of side rail members, each having a front and a back face; a flexible securing rod having a length substantially corresponding to the length of the loop and a rod diameter less than the diameter of the loop. A first and second cross bar members inter-relate with the side rail members. A first cross bar member secured to corresponding upper portions of said side rail members, said first cross bar member having a lower surface and a generally curved shape so as to project at least partially outwardly away from said respective back faces of said side rail members; a second cross bar member secured to corresponding lower portions of each of said side rail members and cooperating with said first cross bar member so as to hold said side rail members in substantially parallel relation, said second cross bar member being substantially parallel to said first cross bar member. In this embodiment, the second cross bar member is tubular and has a generally curved shape so as to project at least partially outwardly away from said respective back faces of said side rail members. The second cross bar member defines an internal conduit with a longitudinal slot opening on a face of the second cross bar member. This slot has a width that is greater than the thickness of the fabric of the sling and less than the diameter of the flexible securing rod; the slot further having a length at least about the width of the fabric sling. The conduit has a diameter greater than the flexible rod and twice the thickness of the fabric of the sling, the conduit thus being configured to retain the rod when inserted into the lateral pocket loop and the conduit. The second cross bar member further includes at least one access notch along the longitudinal slot opening into the conduit, formed by a widening of the slot on the face of the second cross bar member, wherein the access notch is at least as wide as the flexible rod, and further wherein the notch is long and wide enough to enable the insertion of the sling lateral pocket loop into the conduit and the insertion of the securing rod into the sling loop while the sling loop is inserted into the conduit. The notch is located at a point along the slot that substantially corresponds to the pocket opening when the sling loop is substantially inserted into the conduit. A support bar member may be secured to the first cross bar member. This support bar member may have an upper surface and being substantially curved so as to extend in an arc pattern substantially similar to said first cross bar member, with the support bar member being secured such that a gap is created between the lower surface of the first cross bar member and the upper surface of the support bar member extending from an inside surface of each all the way through to an outside surface of each. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a right side view of an exemplary chair showing one embodiment of the present invention. 
         FIG. 2  is a rear elevation view of the back frame and backrest elements of the chair assembly of the present invention. 
         FIG. 3  is a bottom cross-sectional view of the upper backrest assembly of one embodiment of the present invention, taken along the line of  FIGS. 1 and 2 . 
         FIG. 4  is a bottom plan view of one embodiment of the bottom cross bar member of the present invention. 
         FIG. 5  is a right side cross-sectional view of the upper backrest assembly portion of one embodiment of the present invention, taken along the line V-V of  FIGS. 2 and 3 . 
         FIG. 6  is a right side cross-sectional view of the lower backrest assembly portion of one embodiment of the present invention, taken along the line VI-VI of  FIG. 4 . 
         FIG. 7   a  is a perspective view of an alternative embodiment for the cross bar member. 
         FIG. 7   b  is a perspective view of an alternative embodiment for the notch placement in the cross bar member. 
         FIG. 7   c  is a perspective view of an alternative embodiment for an insertion slot placement in the cross bar member. 
         FIG. 7   d  is a perspective view of an alternative embodiment for a short insertion slot placement in the cross bar member. 
         FIG. 8  is a side view of an alternative embodiment for the lower cross bar member. 
         FIG. 9  is a view of the loop and rod within the lower cross bar. 
         FIG. 10  is a view of the wing notch within the lower cross bar. 
         FIG. 11  is a view of the rear of the chair with the present invention as the lower cross bar. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIGS. 1 through 10 , the present invention provides a single frame sling chair  10 , having a rigid frame  12 .  FIG. 1  shows an overall, right side view of one embodiment of a chair according to the present invention, including rigid frame  12  comprising frame side rails  14 , seat  16 , armrests  18  and leg portions  20 . A backrest assembly  22  is also shown, including upper backrest assembly  24  and lower backrest assembly  26 . Upper backrest assembly portion  24  includes top cross bar  28  and support bar  30  that may be detachable, described more completely hereafter. Top cross bar  28  may be integrally formed with top element  32  and connective fascia  34 , or may be secured to top element  32  and connective fascia  34  as separate members. Top cross bar  28  is secured to an upper inner portion of the side rails, and acts as a spreader between the frame side rails  14 . The bottom cross bar  38  is secured to a lower inner portion of the side rails, and acts in concert with the top cross bar  28  as a spreader between the frame side rails  14 , as shown in  FIG. 2 . Lower backrest assembly portion  26  may take a variety of forms, as detailed further herein. 
     As shown in  FIGS. 1 and 2 , one version of lower backrest assembly portion  26  includes bottom cross bar  38  which is secured to frame side rails  14  and acts as a spreader to hold frame side rails  14  apart. Bottom cross bar  38  cooperates with top cross bar  28  to hold frame side rails  14  in substantially parallel relation. A backrest, such as a sling fabric member  33 , is secured to the upper backrest assembly  24  and lower  26  backrest assembly to provide body support to individuals using the sling chair  10  of the present invention. Sling fabric member  33  may include at least a portion of elastic material which allows for a taut appearing backrest while stretching during installation. 
     In the embodiment as shown in  FIG. 2 , top cross bar  28  and bottom cross bar  38  are provided in substantially parallel relation. The top and bottom crossbars  28 ,  38  are provided of a curved or concave shape generally, and can be solid or hollow. As shown in  FIGS. 1 and 2 , the top and bottom crossbars  28 ,  38  project at least partially outwardly away from respective frame side rail back faces  15 . The top and bottom crossbars  28 ,  38  can be any of a variety of section shapes, and can be adapted to accept a decorative connective fascia  34  as part of or an attachment to top cross bar  28 , as shown in the exemplary embodiment of  FIG. 2 . Decorative side castings  35  can also be provided as shown in  FIG. 2  so as to flank sling fabric member  33 . The sectional shape of frame side rails  14  as well as that of support bar  30  can be circular, oval, square, or other shape, for example. Further, support bar  30  and frame side rails  14  can be solid or hollow. 
     The remainder of the chair frame can have any arrangement for a seat bottom  16 , it may have armrests  18  or no armrests, and it may have any number of leg portions  20 , or a pedestal instead of legs, and may be a rocker, swivel chair, swivel-rocker, swivel-glider, or a rigid monolithic frame. 
     The method of securing top cross bar  28  and bottom cross bar  38  members to frame side rails  14  can be by conventional means, such as by welding or by providing the frame side rails  14  with open interior slots for receiving respective ends of top and bottom cross bar members  28 ,  38  (not shown). The method of securing sling fabric member  33  to top and bottom cross members involves upper  24  and lower  26  backrest assemblies. Upper backrest assembly  24  comprises at least top cross bar member  28  and detachable support bar  30 . As shown in  FIGS. 2 ,  3  and  5 , detachable support bar  30  is provided with a base portion  41  and a scaffold portion  42 , wherein scaffold portion  42  can be “c”-shaped as shown for receiving a substantially rigid rod  50 . As shown in  FIG. 5 , rod  50  is placed through a loop  40  forming a lateral pocket in sling fabric member  33 , wherein the sling loop  40  and rod  50  rest in the channel  88  ( FIG. 7 ) created by scaffold portion  42 . Loop  40  can be formed, for example, by bending sling fabric member  33  edge back upon itself and securing the sling fabric member  33  to itself, such as via a hem or similar method. A portion of sling fabric member  33  thus rests in the gap  43  created by the base portion  41  of support bar  30  and cross bar member  28 . Thus, gap  43  is between first cross bar member  28  and support bar member  30 , extending from an inside surface of each, facing a seated individual, all the way through to an outside surface of each, so that loop  40  of sling fabric member  33  may rest in scaffold portion  42 . The support bar  30  can be secured to the bottom face  45  of top cross bar  28  using screws  46  mating with a first set of internal threads  47  in base portion  41  and top cross bar  28 , for example. Alternative means of fastening support bar  30  to top cross bar  28  can be employed, such as sheet metal screws, hook and loop fasteners, clamps, or malleable plug members extending from support bar  30  into openings in top cross bar  28 , for example. 
     As shown in  FIGS. 2 ,  4  and  6 , lower backrest assembly  26  comprises at least bottom cross bar  38  and flexible rod  60 . As shown in the versions of  FIGS. 2 and 6 , bottom cross bar  38  can include an upper portion  52  and a lower portion  53  which join together at respective ends  38   a  and  38   b , and which have respective inside walls  54   a  and  54   b , outside walls  55   a  and  55   b  and interior facing walls  56   a  and  56   b . In some versions, cross bar member  38  can be formed as a unitary, monolithic piece, or in other versions it can be formed by securing respective portions  52  and  53  together at ends  38   a  and  38   b  through welding or other attachment means. In this example, the interior facing walls  56   a  and  56   b  cooperate to form a through-and-through slot  44 . In this way, slot  44  extends between the upper portion  52  and the lower portion  53  and through said second or bottom cross bar member  38 . As shown in  FIG. 2 , slot  44  can extend for substantially the length of upper  52  and lower  53  portions. As shown in  FIG. 6 , the end of fabric sling member  33  opposite the end secured to upper bracket assembly is provided with a loop  58  for flexible rod  60 . Loop  58  can be formed in a manner similar to that described for forming loop  40 . Flexible rod  60  and sling loop portion  58  are then retained against outside walls  55   a  and  55   b , which are respectively provided with inwardly extending portions  57   a  and  57   b  for such purpose. In one embodiment as shown in  FIG. 6 , inwardly extending portions  57   a  and  57   b  are arcuate in cross-section. Portions  57   a  and  57   b  assist in providing the backrest assembly  22  with a low profile, minimizing the extent of rod and sling extension outside of the plane formed by outside walls  55   a  and  55   b , which in turn minimizes sling fabric member  33  exposure to unnecessary wear and tear. As shown in  FIGS. 4 and 6 , the securing of sling fabric member  33  within lower bracket assembly  26  can be optionally enhanced through the employment of one or more machine screws  64  extending through openings  66  in bottom cross bar member  38  and mated with a second set of internal threads  65  in upper portion  52 , or other similar securing element. In one embodiment of the invention, a screw receiving member such as a nut having an interior threaded surface is maintained within walls of bottom cross bar  38  so as to receive machine screw  64  while not extending outwardly of the upper portion  52  of bottom cross bar  38 . In this way, minimum visibility of attachment elements such as nuts and bolts can be maintained, which enhances the aesthetic qualities of the present invention. 
     It will be appreciated that the shape of top cross bar  28  and bottom cross bar  38  can be adapted to suit particular chair requirements in accordance with the present invention. For example, the top cross bar  28  can have a rounded rectangle cross-sectional shape, as shown in  FIG. 5 , or can have a square, hexagonal, octagonal or other polygonal shape. Bottom cross bar  38  can have a primarily rectangular shape with arcuate interior wall segments  57   a  and  57   b  as shown in  FIG. 6  and described earlier. Alternatively, bottom cross bar  38  can have a square, hexagonal, octagonal or other polygonal shape. In one embodiment, bottom cross bar  38  has an octagonal shape and adjacent edges establish a receiving channel for substantially rigid rod  50 , flexible rod  60  and loop  58  again minimizing the outward extension of the loop  58  and rod  50 , flexible rod  60  beyond the lower backrest assembly  26 . In a further embodiment, a metal frame member (not shown) can be secured to upper  52  and lower  53  portions of bottom cross bar  38  to conceal and protect sling fabric member  33  and loop  58 . 
     By placing the sling fabric member  33  entrapment at the top and bottom in the top cross member  28  and bottom cross member  38 , rather than in the side rails  14 , the invention facilitates the creation of a comfortable concave shape to the back rest assembly  22 . Also, the invention thereby allows for shorter looped hems and rods than would exist if the sling fabric member  33  were attached to the side rails  14 . The invention also permits sturdier and more rigid frame  12  construction and leaves open more design possibilities for accessory items. 
     The method of assembling the backrest  22  to the frame  12  according to the present invention can occur in several ways. In one exemplary way, rigid frame  12  is provided with top cross bar member  28  and bottom cross bar member  38  secured to side rails  14  as shown in  FIG. 2 . Sling fabric member  33  is provided with loops  40 ,  58  at two ends thereof. Loop  58  is manipulated in through slot  44  in lower cross bar  38  so as to be positioned somewhat adjacent to wall portions  57   a  and  57   b . Flexible rod  60  is then manipulated through loop  58  such that any tension applied to the remainder of sling fabric member  33 , such as pulling on sling fabric member  33  from a location on the interior of lower cross bar member  38 , will result in loop  58  contacting wall portions  57   a  and  57   b . Machine screws  64  and nuts or equivalent attachment means can assist in retaining sling fabric member  33  in place with respect to bottom cross bar  38 . 
     Next, rod member  50  is placed through loop  40  of sling fabric member  33 , and this arrangement is positioned over base portion  41  of support bar  30  and within scaffold portion  42 . Support bar  30  is then raised so as to align with the bottom face  45  of top cross bar member  28 . Screws  46  or similar attachment means can then be manipulated through base portion  41 , sling fabric member  33  and top cross bar member  28  to securely maintain support bar  30  and sling fabric member  33  to top cross bar member  28 . 
     In an alternative embodiment or version, lower backrest assembly  26  may have a monolithic bottom cross bar  38  formed from a single tubular piece, for which no screws are required in assembling or fixing sling fabric member  33  to bottom cross bar  38 . With reference to  FIGS. 7 &amp; 8 , an aspect of such an embodiment is that a tubular bottom cross bar  38  defines a internal conduit  88  or with a tubular interior and a longitudinal slot  84  opening on a face of second tubular cross bar  80  for access to internal conduit  88 . In this version, the back rest assembly  22  for a sling chair  10  will involve a fabric sling member  33  having a height and width so as to form an upper end and a lower end corresponding to upper backrest assembly  24  and lower backrest assembly  26 . Sling fabric member  33  includes a loop  58  across the lower end of the sling fabric member  33 , with loop  58  having a loop diameter and defining at least one side pocket opening at one end. Some embodiments of sling fabric member  33  may be a strap, band, or sheet filling the entire back height and width or more than two thicknesses wide as compared to two thicknesses of the sling fabric member  33  fabric used. The sling fabric member  33  also has a loop  58  across the upper end of the sling fabric member  33  with a loop diameter, the loop  58  defining at least one side pocket opening at one end. An aspect is slot  84  running longitudinally down the face of the tubular cross bar  80 , with embodiments of slot  84  as wide as at least two thicknesses of the fabric of the sling fabric member  33 . This allows for the fabric of the sling fabric member  33  to be folded over upon itself forming loop  58 . 
     Other embodiments may involve a configuration of loop  58  in which sling fabric member  33  is folded within itself, so that a single thickness is presented through the slot. 
     In an embodiment the present invention may have an upper cross bar  80   u  or a lower cross bar  80   b  that faces rearward as compared to the backrest assembly  22 . In this manner tension of the sling fabric member  33  may be looped over the upper cross bar  80   u  to the lower cross bar  80   b  and looped under the lower cross bar  80   b  to present a backrest assembly  22  which presents an entirely sling fabric member  33  to the back of the user. In this manner the tension of the sling fabric member  33  is spread evenly across a smooth surface of the upper cross bar  80   u  and lower cross bar  80   b . The ends of the tubular cross bar  80  may be enclosed for decorative purposes. The upper cross bar  80   u  and/or lower cross bar  80   b  may be mounted to the frame side rails  14  so that slot  84  is facing in any desired position rotationally around the longitudinal axis. The first cross bar member is attached to the side rail upper inner portions and the second cross bar member is attached to the side rail lower inner portions similar to  FIG. 2 . 
     The notch  83  may have a centerline which is congruent with the centerline of the slot  84  or may be offset so that the minimum notch  83  length and height meets the requirements as noted by the equations below. 
     As with other embodiments, a pair of frame side rails  14  are included, each having a front and a back face  15 . A flexible rod  60  is provided for use with loop  58 . Flexible rod  60  may be in a cross-section a square, rectangle, triangle or of multiple forms and has a length substantially corresponding to the length of the loop  58  and a diameter less than the diameter of the loop  58 . The upper cross bar  80   u  is secured to corresponding upper portions of said side rails  14 , with the upper cross bar  80   u  having a lower surface and a generally curved shape so as to project at least partially outwardly away from said respective back faces of said frame side rail  14 . Likewise, a lower cross bar  80   b  is secured to corresponding lower portions of each of said frame side rail  14  and has a generally curved shape so as to project at least partially outwardly away from said respective back faces of said frame side rails  14 . Lower cross bar  80   b  thus cooperates with said upper cross bar  80   u  so as to hold said frame side rails  14  in substantially parallel relation, with said lower cross bar  80   b  being substantially parallel to said upper cross bar  80   u.    
     An aspect of this embodiment is that lower cross bar  80   b  is tubular and defines an internal conduit  88  with a longitudinal slot opening  84  on a face of the lower cross bar  80   b . Slot  84  has a width that is greater than the thickness of the fabric of sling fabric member  33  and less than the diameter of the flexible rod  60 ; in addition, slot  84  may generally run a length at least about the width of the fabric sling member  33 . An aspect of lower cross bar  80   b  is that conduit  88  has a diameter greater than the flexible rod  60  combined with twice the thickness of the fabric of the sling fabric member  33 ; thus, conduit is configured to retain the flexible rod  60  within the loop  58  when inserted into the conduit  88 . 
     Lower cross bar  80   b  includes at least one access notch  83  along the longitudinal slot  84  opening into the conduit  88 . This may be a widening of the slot  84  on the face of the lower cross bar  80   b  to be at least as wide as the flexible rod  60  and loop  58  assembled. The sizing and configuration of notch  83  is to be long and wide enough to enable the insertion of the loop  58  into the conduit  88  and the insertion of the flexible rod  60  into the loop  58  while the loop  58  is inserted into the conduit  88 . The slot  84 , notch  83  and conduit  88  of the upper cross bar  80   u  and the lower cross bar  80   b  must minimally meet the following requirements for an embodiment where the sling fabric member  33  is of a double thickness where: 
     d rod =the flexible rod  60  diameter 
     F=thickness of the fabric sling back  33   
     F f =thickness of the fabric sling back  33  fold when inserting the flexible rod  60  and fabric sling back  33  into the notch  83  at a maximum of 45 degrees 
     C=compression of flexible rod  60  material when bent at 45 degrees to the conduit  88 
         Conduit  88  inside diameter min =d rod +2F   Slot  84  width min =2F   Notch  83  width min =d rod +2F+(F f )+C       

               Notch   ⁢           ⁢   83   ⁢           ⁢     length   min       =         d   rod     +     2   ⁢   F         Cos   ⁢           ⁢   45             
Applying the above equations assuming:
 
     d rod =3 mm (nylon) 
     Fabric thickness=0.5 mm 
     Fabric compression on insertion=F f =1.0 mm 
     Compression of rod=C=0.1 mm 
     Slot width=2F=2(0.5 mm)=1.0 mm 
     Notch width=d rod +2F+(F f )+C=3+1+1+0.1=5.1 mm 
               Notch   ⁢           ⁢   length     =           d   rod     +     2   ⁢   F         Cos   ⁢           ⁢   45       =         3   +   1     .525     =     7.6   ⁢           ⁢   mm               
Applying the above equations for a single thickness fabric assuming:
 
     d rod =3 mm (nylon) 
     Fabric thickness=0.5 mm 
     Fabric compression on insertion=F f =1.0 mm 
     Compression of rod=C=0.1 mm 
     Slot width=F=0.5 mm Notch width=d rod +F+(F d )+C=3+0.5+1+0.1=4.6 mm 
     
       
         
           
             
               Notch 
               ⁢ 
               
                   
               
               ⁢ 
               length 
             
             = 
             
               
                 
                   
                     d 
                     rod 
                   
                   + 
                   
                     0.5 
                     ⁢ 
                     F 
                   
                 
                 
                   Cos 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   45 
                 
               
               = 
               
                 
                   
                     3 
                     + 
                     0.5 
                   
                   .525 
                 
                 = 
                 
                   5.8 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   mm 
                 
               
             
           
         
       
     
     Accordingly, the notch  83  is located at a point along the slot  84  corresponding to the side opening of loop  58 , when the loop  58  is substantially inserted into the conduit  88 . The presence of the notch  83  allows for insertion of at least a portion of the flexible rod  60  residing within the loop  58  assembly into the cross bar members  80   u ,  80   b  after assembly of the cross members  80   u ,  80   b  between the frame side rails  14 . The notch  83  may be shaped as a flat where it abuts the slot  84 , tapered, rounded or the flat corners folded outwardly and down perpendicular to the corner to assist in flexible rod  60  and sling fabric member  33  into channel  88 . 
     Thus, with this embodiment no screws are needed to affix sling fabric member  33  to lower cross bar  80   b . In this manner the flexible rod  60 , and loop  58  are captured within the upper cross bar  80   u  and lower cross bar  80   b . This eliminates the need for both support bars  30 , mounting hardware to provide a slit and assembly time or tools for assembly. In practice, this results in a clean, secure fitting sling fabric member  33  that is easier to assemble. 
     Assembly of the sling fabric member  33  into the upper cross bar  80   u  or lower cross bar  80   b  may occur after the upper cross bar  80   u  or lower cross bar  80   b  is assembled between and to the frame side rails  14 . The notch  83  may be facing forward in relation to the backrest assembly  22  or in a rearward direction allowing for insertion of the rod  50 , flexible rod  60  and loop  58  from the front or rear of upper cross bar  80   u  or lower cross bar  80   b . In a rearward facing position, the sling fabric member  33  and rod  50  may be inserted in upper cross bar  80   u , then looped over the upper cross bar  80   u  concealing the upper cross bar  80   u  from the user facing the front of the sling chair  10 . The remaining sling fabric member  33  and flexible rod  60  may be looped under the lower cross bar  80   b  and inserted into the rearward facing notch  83  of the lower cross bar  80   b . This method conceals both the upper cross bar  80   u  and the lower cross bar  80   b  from the user facing the sling chair  10 . The notch  83  allows for simple insertion of the rod  50 , flexible rod  60  and loop  58  and does not need to have a size or shape to enable the manipulation of weaving wicker as described in U.S. Pat. No. 7,481,495 to Wang, et al. hereby fully incorporated by reference. 
     It is anticipated that the maximum force for insertion depending on the flexible rod  60  and loop  58  material flexibility will be in the range of 3.4-8.4 pounds force for insertion at an angle of up to 45 degrees. As the notch  83  height becomes larger and without obstruction by other components the insertion angle will decrease and therefore decrease the required insertion force. This clean appearance may be seen by the finished product.  FIG. 9  is an isometric view showing the clean appearance of the sling fabric member  33  protruding through the slot  84 . As discussed above, during assembly no screws are required for lower cross bar  80   b . Instead, loop  58  of sling fabric member  33  and flexible rod  60  are inserted into conduit  88 , a much quicker and less laborious approach, reducing assembly cost and time. 
     In another embodiment ( FIG. 7   c ) the upper cross bar  80   u  and lower cross bar  80   b  has a slot  84  from which the sling fabric material  33  protrudes from the upper cross bar  80   u  or lower cross bar  80   b . On the opposite side of the upper cross bar  80   u  or lower cross bar  80   b  is an insertion slot  86  which has a length equal to or greater than the slot  84  and is wider than the loop  58  and flexible rod  60 . In this manner the sling fabric member  33  is assembled by inserting the sling fabric member  33  through the slot  84  in an inverse manner such that the sling fabric member  33  protrudes into the conduit  88  and through the conduit  88  through the insertion slot  86  on the opposite side of the upper cross bar  80   u  or lower cross bar  80   b . The flexible rod  60  is then inserted into the loop  58  and the sling fabric member  33  is then urged inversely from the insertion direction such that the flexible rod  60  and loop  58  then resides in the conduit  88  against the back of the slot  84 . In that the flexible rod  60  and loop  58  is of a greater diameter than the width of the slot  84 , the flexible rod  60  and loop  58  serve to restrict any further movement of the sling fabric member  33 , thus securing the sling fabric member  33 . 
     In yet another embodiment ( FIG. 7   d ) the upper cross bar  80   u  or lower cross bar  80   b  is fashioned as described above, except it has a short insertion notch  89  has a length less than the slot  84 . The short insertion notch  89  may be located at either end of the upper cross bar  80   u  or lower cross bar  80   b . The sling fabric member  33  is inserted into the slot  84  in an inverse direction into the conduit  88  where it remains within the conduit in a longitudinal direction. The end of the loop  58 , is then located and flexible rod  60  is inserted into the loop  58  through the short insertion notch  89 . As in the manner noted above, the sling fabric member  33  is then pulled inversely from the insertion direction where the flexible rod  60  located within the loop  58  constrain the sling fabric member  33  from pulling back through the slot  84 . 
       FIG. 8  is a sectional view showing the lower cross bar  80   b  with the flexible securing flexible rod  60  inside the loop  58  and contained within the conduit  88 . In this embodiment the loop  58  is at the respective end  38   b  of the sling fabric member  33 . Two layers of the fabric of the sling fabric member  33  are shown protruding through the slot  84 . 
       FIG. 9  is an isometric view depicting the lower cross bar  80   b  showing in detail the mating of the lower cross bar  80   b  to one of the side rails  14 . Also shown in this figure is the location of the notch  83  in relation to the slot  84 . The lower cross bar  80   b  may be rotated around the longitudinal axis in order to locate the slot  84  in a desired position. A double thickness of the fabric of the sling fabric member  33  are shown protruding through the slot  84  although the flexible rod  60  may be within the loop  58  where only one thickness of the fabric protrudes through the slot  84 . The notch  83  is medially from the end of slot  84 , but not at the end of slot  84 . Medially is defined as lying or extending toward the middle, more specifically not abutting the end of the slot or cross bar. This allows for the flexible rod  60  and loop  58  to be retained by the closed end of the internal conduit  88 . 
       FIG. 10  shows a view of a wing notch  90  within a tubular cross bar  80 . Wing notch  90  does not reside axially along the slot  84 , but is angled following the contour of the tubular cross bar  80 . This allows for insertion of the flexible rod  60  within the loop  58  to be inserted at an angle assisting in manufacturability. 
       FIG. 11  shows a rear view of a sling back chair  10  with the lower cross bar  80   b  securing the sling fabric member  33  to the lower portion of the frame side rails  14 , thus in combination with the top cross bar member  28  forming a sling fabric member back rest surface. 
     In another embodiment the sling fabric member  33  including the flexible rod  60  and loop  58  may be removed from the cross bar members  80   u ,  80   b  through the notch  83 . The sling fabric member  33  may then be removed from the flexible rod  60  and replaced with a sling fabric member  33  of a different pattern, color, size or shape. 
     Upper backrest assembly  24  may take the form of any of the variations described above. For example, a support bar  30  may be secured to said top cross bar  28 , with said support bar  30  having an upper surface and being substantially curved so as to extend in an arc pattern substantially similar to said top cross bar  28 , said support bar  30  member being secured such that a gap is created between the lower surface of the top cross bar  28  and the upper surface of the support bar  30  extending from an inside surface of each all the way through to an outside surface of each. In additions, the other variations described above may used with this embodiment, as applicable. 
     In any embodiment, upper cross bar  80   u  or lower cross bar  80   b  may be paired with top cross bar  28  or bottom cross bar  38  such that any embodiment involving upper cross bar  80   u  may have a bottom cross bar  38  or any lower cross bar  80   b  may have a top bar  28 . 
     The process to assemble the chair back are: 
     1) Attaching the first cross bar member and the second cross bar member to the first side rail end portion and the second side rail end portion so that the first and second cross bars are generally parallel to each other and perpendicular to the frame side rails. 
     2) The first flexible securing rod is fully inserted within the first loop of the sling fabric member. 
     3) The first flexible securing rod inside the first loop of the sling fabric member is inserted into the first notch of the first cross bar member and into the first internal conduit such that the sling fabric extends through the slot. 
     4) The first flexible securing rod and the first loop are fully positioned in the first internal conduit such that the fabric extends the length of the slot; 
     5) The sling fabric member second edge is pulled toward the second cross bar member extending to the second cross bar member with sufficient material to be secured to the second cross bar member. 
     6) The sling fabric member second edge is then secured to the second cross bar member. 
     In an alternative embodiment, the second cross bar member is shaped like the first and would employ the same steps as shown in paragraph [0046] continuing from step  5  and alternative steps  6  and  7 . 
     6). providing the second flexible securing rod having a length substantially corresponding to the length of the second loop and a rod diameter less than the diameter of the second loop and inserting the second flexible securing rod within the second loop of the sling fabric member; 
     7). inserting the second flexible securing rod and the second loop of the sling fabric member into the second notch of the second cross bar member into the second internal conduit such that the sling fabric extends through the slot; and 
     positioning the second flexible securing rod and the second loop fully in the second internal conduit such that the fabric extends the length of the slot. 
     Simply put, and in reference to  FIG. 9 , the chair back has at least two side rails  14  placed approximately vertical and substantially parallel to each other. A sling fabric member  33  is preassembled having a first loop  58  along a first edge and a second loop  58  along a second edge, the first loop  58  being substantially the length of the first edge and of a desired loop diameter and the second loop  58  being substantially the length of the second edge and of the desired loop diameter. The both loops  58  run the length of the sling fabric member  33  parallel to each other. 
     There is least one flexible rod  60  which can be used at times interchangeably with any crossbar  80  of the same configuration. The flexible rod  60  has a diameter smaller than the desired loop diameter in order to fit inside the loop  58 . Should two cross members  80   u ,  80   b  be used in the construction of the chair  10  there would be a first flexible securing rod and a second flexible securing rod. 
     The first flexible rods  60  are the length of the first edge and is inserted within the first loop  58 , and the second flexible rod  60  is the length of the second edge and is inserted within the second loop  58 . 
     There is at least one cross bar  80  having a hollow conduit  88 , a longitudinal slot  84  substantially the length of the cross bar  80 , the slot  84  having a width greater than twice the thickness of the sling fabric member  33 , the slot  84  width less than the diameter of the flexible rod  60  and loop  58 , with a notch  83  widening the slot  84  axially shown at the left end of  FIG. 9 . The width of the notch  83  is minimally greater than the diameter of the flexible rod  60  and desired loop diameter and the length approximately twice the width. 
     There is at least a first cross bar  80  and a support bar  28 ,  38  (shown in  FIG. 5  or  FIG. 6 ) or possibly a second cross bar  80  ( 80   b  and/or  80   u ) attached horizontally between the side rails  14  and generally parallel to each other. The first loop  58  and first flexible rod  60  are inserted in the first cross bar  80  notch  83  and urged completely into the conduit  88  with the sling fabric member  33  protruding through the slot  84  and the second loop  58  and second flexible rod  60  are inserted in the second cross bar  80  notch  83  and urged completely into the conduit  88  with the sling fabric member  33  protruding through the slot  84  forming a sling fabric member back rest surface. 
     It is noted that the sling fabric member back rest surface retains a tension when an applied pressure of 15 kilograms is applied over a single 5 cm square area to the sling fabric member back rest surface plane at approximately a midpoint between the side rails where the force applied deflects the sling fabric member surface from 0.5 cm to 30 cm. 
     The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the claims of the application rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.