Patent Publication Number: US-8122630-B2

Title: Rib support of folded material

Description:
FIELD OF THE INVENTION 
     The present invention pertains to support structures for receiving rib members and in particular to support structures used with flexible signs. 
     BACKGROUND OF THE INVENTION 
     Roadside construction projects must oftentimes be carried out without stopping roadway traffic. Accordingly, measures are required to maintain safety in the work environment. Temporary warning signs are becoming increasingly popular since the geographic configuration of a work site frequently changes before the work is finished. Also, with the advent of more powerful, complex equipment, roadway repairs and roadside work projects can be completed within a relatively short time, such that erection of permanent warning signs would not be practical. 
     One class of temporary warning signs includes sign panels made of flexible material, which are maintained in a taut, planar position by backing members extending across the sign panel. These backing members frequently comprise ribs of fiberglass or aluminum material. It has become popular to arrange the sign panel so that it can be quickly and easily detached from the supporting ribs and rolled up for compact storage. Thus, the need arises for releasably securing the rib members to the flexible sign panel. 
     Initially, pockets for receiving the ends of supporting ribs were formed by joining relatively small pieces of fabric to the corners of the flexible sign panels, so as to form a rib-receiving pocket between the fabric and the sign panel. Roadway warning signs are employed out of doors and are thereby subjected to wind gusts and traffic induced wind bursts which expose the flexible sign panel to substantial amounts of strain, particularly where rib supports are attached to the sign panel. Accordingly, with static and vibratory wind loadings applied to the sign panel, the ends of the supporting ribs were found to wear through the pocket material, requiring substantial repairs to be made to the sign assembly. In time, steps were taken to provide more secure attachment of supporting ribs to portions, usually outside corners, of the sign panel. For example, fabric pockets have been employed in U.S. Pat. Nos. 3,899,843 and 3,526,200, while resilient straps have been proposed in U.S. Pat. No. 4,592,158. Rigid panel pockets have also been proposed in U.S. Pat. Nos. 4,426,800 and 4,490,934. Despite these advancements, improvements in rib supports are still being sought. 
     SUMMARY OF THE INVENTION 
     The present invention provides a novel and improved rib-engaging support that minimizes the disadvantages associated with the prior art arrangements and provides advantages in construction, mode of operation and use. One embodiment of the rib-engaging support is made from a unitary web that includes a serial succession of four panels, including two inner panels and two outer panels. Each panel has the shape of an isosceles trapezoid, with a base side and a top side parallel to each other, and with a pair of equal sides extending between the base side and the top side. The inner panels have the same, first size and are joined together at their bases. The outer panels have a second larger size and their top sides are joined to the top sides of respective inner panels. When the web is folded, the inner panels are folded one on top of the other and the outer panels are folded one on top of the other, with the inner panels on top of the outer panels. A rib-receiving pocket is formed between the inner panels and the outer panels. Marginal edge portions of the panels are provided for securement to a sign panel using adhesive or stitching techniques. The rib-receiving pocket is preferably formed by stitching the panels together. In use, the rib-receiving pocket has a line of stitching between the free end of the support rib and an edge of the rib-engaging support that includes nested folds at the places where the inner and outer panels are joined together. 
     In another embodiment, the present invention provides a flexible warning sign comprising a flexible message panel capable of assuming a substantially flat configuration for displaying a message, and at least one support rib removably joined to the flexible message panel. Also included is a rib-engaging support is made from a unitary web that includes a serial succession of four panels, including two inner panels and two outer panels. Each panel has the shape of an isosceles trapezoid, with a base side and a top side parallel to each other, and with a pair of equal sides extending between the base side and the top side. The inner panels have the same, first size and are joined together at their bases. The outer panels have a second larger size and their top sides are joined to the top sides of respective inner panels. When the web is folded, the inner panels are folded one on top of the other and the outer panels are folded one on top of the other, with the inner panels on top of the outer panels. A rib-receiving pocket is formed between the inner panels and the outer panels for receiving an end of the support rib. Marginal edge portions of the panels are provided for securement to a sign panel using adhesive or stitching techniques. The rib-receiving pocket is preferably formed by stitching the panels together. In use, the rib-receiving pocket has a line of stitching between the free end of the support rib and an edge of the rib-engaging support that includes nested folds at the places where the inner and outer panels are joined together. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic elevational view of a rib-engaging support; 
         FIG. 2  is a cross-sectional view taken along the line  2 - 2  of  FIG. 1 ; 
         FIG. 3  is a fragmentary cross-sectional view taken along the line  2 - 2  of  FIG. 1 ; 
         FIG. 4  is a schematic plan view of a web from which the rib-engaging support is constructed; 
         FIG. 5  shows the rib-engaging support at an intermediate stage of construction; 
         FIG. 6  is a schematic elevational view of a prior art support; 
         FIG. 7  is an exploded cross-sectional view taken along the line  7 - 7  of  FIG. 6 ; 
         FIG. 8  is a fragmentary cross-sectional view taken along the line  7 - 7  of  FIG. 6 ; 
         FIG. 9  shows fabric panels from which the support of  FIG. 6  is constructed; 
         FIG. 10  shows one of the fabric panels; 
         FIG. 11  shows the other fabric panel; 
         FIG. 12  is a schematic diagram of an isosceles triangle; 
         FIG. 13  is a schematic diagram of an isosceles trapezoid; 
         FIG. 14  is a schematic diagram of a sign assembly with rib-engaging supports; 
         FIG. 15  shows the rib-engaging support of  FIGS. 1-14  applied to a sign panel; 
         FIG. 16  is a schematic elevational view of an alternative rib-engaging support; 
         FIG. 17  is a schematic plan view of a web from which the rib-engaging support of  FIG. 16  is constructed; and 
         FIG. 18  is a schematic elevational view of the rib-engaging support of  FIG. 16  shown attached to a sign panel. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention disclosed herein is, of course, susceptible of embodiment in many different forms. Shown in the drawings and described herein below in detail are preferred embodiments of the invention. It is understood, however, that the present disclosure is an exemplification of the principles of the invention and does not limit the invention to the illustrated embodiments. For use of description, a rib-engaging support embodying the present invention is described herein below in its usual assembled position as shown in the accompanying drawings, and terms such as upper, lower, top, base, horizontal, longitudinal, etc., may be used herein with reference to this usual position. However, the rib-engaging support may be manufactured, transported, sold or used in orientations other than that described and shown herein. 
     Turning now to the Figures, and initially to  FIG. 14 , a lightweight sign assembly is generally indicated at  1 . The sign stand assembly is particularly suited for temporary, roadside work to warn oncoming motorists that they are entering a work zone or an area that otherwise requires their careful attention. Sign assembly  1  includes a sign panel  2  made of flexible fabric, preferably with a reflective coating and bearing a message on one of its faces. When used in a roadside work environment, the sign panel  2  must be maintained in a relatively taut condition, in order to adequately display warning messages to oncoming motorists. Accordingly, a support arrangement is provided for engaging the sign panel  2  at its corners with stretching members. 
     In the illustrated embodiment, two rib support members are employed, and may be made of a flexible material such as fiberglass resin or aluminum, or otherwise constructed so as to be able to bend for insertion into corner pocket support members. In the illustrated embodiment, a vertical support rib  3  extends to the top of sign panel  2 . The sign assembly I is supported from below by a ground-engaging base generally indicated at  4 . Included in the base is a spring dampening assembly  5  and ground-engaging legs  6 . In the illustrated embodiment, vertical support rib  3  extends to base  4  thus, also serving as an upright support member for the sign panel. If desired, a separate upright support member can be provided to extend from base  4 , connecting to vertical rib  3  with a rib-receiving connection, as may be desired. In use, when placed out of doors, sign panel  2  acts as a sail capturing static wind loading and wind bursts which are transmitted to base  4 . Spring-loaded dampener  5  absorbs the wind loading, preventing dislodgment of legs  6  from their contact with the ground. 
     In the illustrated embodiment, sign panel  2  is secured at its bottom portion to rib  3  by fastener  7 , which preferably takes a conventional form of a rivet or the like. A horizontal support rib  8  is secured to vertical rib  3  by rivet or other suitable fastener  9 . Rib-engaging supports  10  are located at the side and top corners of the sign panel  2 . Preferably, the rib-engaging supports  10  are secured to sign panel  2  with stitching but can also be secured with adhesive, welding or mechanical fasteners. In the illustrated embodiment of  FIG. 14 , rib-engaging supports  10  act as corner pockets for receiving the ends of horizontal rib  8  and the top end of vertical rib  3 . 
     During erection of the sign assembly  1 , horizontal rib  8  is flexed in a horizontal plane so as to shorten the horizontal distance to rib-engaging support  10 . The rib is then inserted in the corner pocket, in a manner to be described herein, and is allowed to resume its relaxed position illustrated in  FIG. 14 . The upper end of rib  3  is also flexed in a similar manner for engagement with the upper rib-engaging support  10 . 
     When sign assembly I is no longer required, it is easily disassembled and rolled up for compact storage. Rib  3  is flexed in a vertical plane so as to allow the disengagement of its upper end from the upper rib-engaging support  10 . The horizontal rib  8  is then flexed in a horizontal plane to allow disengagement with the rib-engaging supports  10  located at the sides of sign panel  2 . Rib  8  is then rotated 90° so as to overlay vertical support rib  3  and sign panel  2  is then rolled about the collapsed ribs. Support rib  3  is disengaged from base  4  and the two components are moved to a storage location. Thus, sign assembly  1  can be quickly and easily erected and taken down on short notice, making it suitable for short term deployment. 
     Turning now to  FIGS. 1 and 2 , a rib-engaging support  10  is shown constructed from foldable web material, such as a woven fabric or a sheet of solid but foldable material. As will be seen herein, the rib-engaging support  10  is preferably made from a single integral web which is folded and stitched to provide a number of desirable features. 
       FIG. 2  is a schematic diagrammatic representation of a cross section of rib-engaging support  10 , taken along the line  2 - 2  of  FIG. 1 . In  FIG. 2 , the stitching of  FIG. 1  is removed and the folded layers are opened for illustrative purposes. As shown in  FIG. 2 , the rib-engaging support  10  of  FIG. 1  is constructed from a single integral web  12  which will be described in detail herein with reference to  FIG. 4 . Preferably, rib-engaging support  10  is completely constructed with folding and stitching in the manner described herein. 
     Referring again to  FIG. 1 , rib-engaging support  10  is made of four web layers, two of which,  30   a  and  36   a , are visible in  FIG. 1 . The four layers are stitched together along lines  20   a - 20   c ,  22   a  and  22   b  with lines  20   a - 20   c  forming the rib-receiving pocket  18  having an opening  24  for receiving one end of a support rib, preferably with a relatively close tolerance fit. As can be seen in  FIG. 1 , opening  24  of rib pocket  18  has an enlarged mouth due to angled or tapered stitching segments  20   c . The resulting funnel-shaped opening helps guide the rib for its initial entry into pocket  18 . Stitching segments  20   c  in effect remove a right angle corner thus further reducing stress imparted to the stitching by the rib. The remaining stitching  22   a ,  22   b  extends generally parallel to the outer perimeter of the folded inner panels ( 30 ,  32 —see  FIG. 4 ) collectively indicated at  14 . As can be seen in  FIG. 1 , the folded outer panels ( 34 ,  36 —see  FIG. 4 ) collectively indicated at  16  are of a somewhat larger size so as to form an exposed lip or threshold  26  to aid in orienting the rib end for insertion into pocket  18 . With reference to  FIG. 3 , one end of rib  3  is inserted in pocket  18  and is encased by two inter-nested, unbroken, continuous fabric layers, forming two overlaying layers on either side of rib  3 . 
     Referring again to  FIG. 3 , it can be seen that the present invention provides a cushion of accumulated material at the end of rib  3 . The accumulated material preferably comprises the nested groups of material extending beyond stitching line  20   a  and which include the fold lines  48 ,  50 . As can be seen in  FIG. 3 , this accumulated material provides a collapsible cushion which protects stitching line  20   a  and the fabric in the vicinity of that stitching, particularly, the end of the rib-receiving pocket  18 . With reference to  FIG. 14 , for example, the lateral or horizontal rib device  8  is inserted between opposed rib-engaging supports  10 . It has been found convenient to insert one end of the rib at a time, while pressing the rib against the ground. This allows an operator to apply a bowing force to the rib member, allowing insertion of the remaining free end of the rib into the second rib-engaging support. As will be appreciated by those skilled in the art, ribs made of composite fiberglass material have a relatively large spring constant and can develop a considerable amount of force when bent or deflected in the manner required for insertion in a pair of opposing rib-engaging supports. Prior art designs in which the rib and sign panel are forced directly into the ground, without benefit of a cushion at the rib end concentrates forces in the rib-engaging support on both sides of the pocket stitching (see reference number  91  in  FIG. 6 ). With the present invention, edge surface  28  of the rib-engaging support pocket (see the top of  FIGS. 1 and 3 ) prevents not only poke-through on the inside of the rib-receiving pocket but also prevents abrasion and wearing away of the rib-engaging support on the outside of the rib-receiving pocket. 
     As will now be described in further detail, it is generally preferred that rib-engaging support  10  have the shape of a truncated isosceles triangle or isosceles trapezoid, although other shapes are also contemplated by the present invention. With reference to  FIG. 12 , a diagram of an isosceles triangle is shown having a base B and equal sides X. As is known, sides X have equal lengths, and form equal but opposite angles with base B. In other terms, the sides X form congruent angles with base B. A tip of the triangle is indicated at T and is formed by a broken line generally parallel to base B. If the tip I of the triangle is removed, the figure illustrated in  FIG. 13  results. As is known, the shape illustrated in  FIG. 13  is referred to an isosceles trapezoid, which is a quadrilateral with a line of symmetry bisecting one pair of opposite sides, herein the base B and top Z. making it automatically a trapezoid. The two opposite sides, base B and top Z are parallel to one another and the two remaining sides Y are of equal length. The diagonals of the isosceles trapezoid of  FIG. 13  are of equal length. The base angles formed between sides Y and base B are congruent. With reference to  FIG. 1 , the outer periphery of the illustrated embodiment of rib-engaging support  10  takes the shape of an isosceles trapezoid. As will be seen herein, rib-engaging support  10  is preferably formed by folding an integral web having a serial array of four consecutive panels, each having the shape of an isosceles trapezoid. 
     With reference to  FIG. 4 , blank  12  is preferably formed from a single integral web cut along ten sides to form the shape illustrated. Included in blank  12  is a serial succession of four panels including two inner panels  30 ,  32  and two outer panels  34 , 36 , each panel having the shape of an isosceles trapezoid, with a base side and a top side parallel to each other, and with a pair of equal sides extending between the base side and the top side. The inner panels  30 ,  32  have substantially the same size and are joined together at their bases along fold line  46 . The outer panels  34 ,  36  have a second larger size (that is larger than the size of the inner panels  30 ,  32 ). 
     As will be seen with reference to  FIG. 4 , inner and outer panels  30 - 36  preferably form portions of a continuous integral fabric blank illustrated in  FIG. 4 . The fabric blank has two opposed major surfaces with the major surface visible in  FIG. 4  being designated by a suffix “a” referred to as the top side or top surface. Thus, the top sides of outer panels  34 ,  36  and inner panels  30 ,  32  have upper surfaces designated by the suffix “a.” Accordingly, the top sides of inner panels  30 ,  32  are identified in  FIG. 4  as  30   a ,  32   a  and the top sides of outer panels  34 ,  36  are identified by the reference numbers  34   a ,  36 . The reverse or bottom sides of these surfaces would be identified by the suffix “b.” Accordingly, the opposite surfaces of panels  30 ,  32  are identified as  30   b ,  32   b  and the opposite sides of outer panels  34 ,  36  are identified as  34   b ,  36   b.  With reference to  FIG. 1  portions of the bottom surfaces  32   b ,  34   b  are visible and appear in conjunction with the top sides  30   a ,  36   a  to the folding of the fabric blank. The opposite top and bottom surfaces of the fabric panels are identified in  FIG. 2 . 
     The top sides of the outer panels  34 ,  36  are joined to the top sides of respective inner panels  30 ,  32  along fold lines  48 ,  50 . In  FIG. 4 , the outline of stitching  20 ,  22  is also shown for illustrative purposes. Outer panel  36  is shown with a construction line  52  which, with reference to  FIG. 1 , indicates the exposure of threshold  26 . 
     With reference to  FIG. 4 , rib-engaging support  10  is constructed by folding blank  12  first along fold line  46  so as to overlay the two half portions of blank  12  on top of one another, in the manner illustrated in  FIG. 5 . Thereafter, the resulting intermediate structure is folded about fold lines  50 ,  48  so as to bring the four panels in overlying relationship. 
     The resulting folded construction is shown opened up or expanded in  FIG. 2  for illustrative purposes. As mentioned, each of the four panels has opposite top and bottom sides. With brief reference to  FIG. 4 , the top sides visible in  FIG. 4  have the reference designation a while the reverse sides (not visible in  FIG. 4 ) have the reference designation b. As can be seen in  FIG. 1 , the size of the inner panels such as the inner panel  30 , has the same shape but is smaller than the outer panels such as outer panel  36 . In the fully assembled arrangement of the rib-receiving support  10  as seen in  FIG. 1 , only panel faces  30   a  and  36   a  are visible. As indicated in  FIG. 2 , the inner panels  30 ,  32  are folded one against the other and the outer panels  34 ,  36  are also folded against each other. When fully constructed, the inner panels  30 ,  32  are folded to lay on top of the outer panels  34 ,  36  whose free ends are located at the bottom edge of the rib-engaging support visible in  FIG. 1 . If desired, the bottom free edges of the outer panels in  FIG. 1  can be sewn together before being joined to the sign panel. However, in the preferred embodiment, the rib-engaging support  10  is secured to the sign panel by stitching along the outer periphery of the rib-engaging support. With reference to  FIG. 1 , a peripheral border is provided for this purpose, and the threshold  26  is, in the preferred embodiment, also secured to the sign panel by stitching, and thus is relied upon to secure the free edge. In the preferred construction, rib-engaging supports  10  are overlaid on the sign panel, (such as the sign panel  2  of  FIG. 14 ) and are secured to the sign panel using conventional techniques. In the preferred embodiment, the outer border portions of rib-engaging supports  10  are stitched directly to the sign panel, but may also be secured with adhesives, mechanical fasteners or thermal welding, for example. Thus, if the rib-engaging support is made from a sheet of plastic material, the stitching may be replaced with a welded joinder. These techniques are also possible if a layer of fabric or other material is coated with a weldable coating. 
     Referring to  FIGS. 6-11 , a prior art rib support is generally indicated at  70 . Support  70  is made from two fabric pieces as illustrated in  FIG. 9 , a smaller piece  72  and a larger piece  74 . As indicated in  FIG. 7 , the fabric pieces  72 ,  74  are each folded in an upwardly opening V-shape with the four free ends of  FIG. 7  located at the top of the support of  FIG. 6 . With reference to  FIGS. 10 and 11 , fabric pieces  72 ,  74  are folded along respective diagonal fold lines  76 ,  78  to assume the forms shown in  FIG. 7 . As can be seen for example in  FIG. 9 , the panel  72  has generally the same shape as panel  74 , but is smaller in size. When folded and laid together as indicated in  FIG. 6 , a bottom edge portion  82  of folded piece  74  is exposed. The line of exposure is indicated at  84  in  FIG. 11 . When fully constructed, the fold line  76  of piece  72  is overlaid on construction line  84  in  FIG. 11 . 
     The pieces  72 ,  74  are secured together with stitching  88  so as to form a rib-receiving pocket  90  having an opening  92 . The outline of stitching  88  is shown in  FIG. 10  for illustrative purposes. Stitching  88  secures four layers of fabric together, with two layers of fabric piece  72  overlaid on top of two folded layers of fabric piece  74 . With reference again to  FIG. 6 , the top of pocket  90  is formed by stitching  94  and is backed up by stitching  96  in case stitching  94  should fail. As can be seen in the cross-sectional view of  FIG. 8 , the upper ends of folded fabric pieces  72 ,  74  are located at the upper end of  FIG. 8 . Support rib  3  disposed in pocket  90  is restrained in an upward direction only by stitching  94 . Over time, when subjected to static and dynamic wind loadings, rib  3  exerts substantial forces on pocket  90 , thereby occasioning failure of stitching  94 . With reference to  FIG. 6 , substantial point loadings are exerted on the corners  98  of the stitching. With the integrity of stitching  94  compromised, forces are transferred to stitching  96  with concentrated point loadings. The result is failure of the sign assembly requiring the sign panel with attached supports to be removed for repair or replacement. 
     As can be seen with reference to  FIGS. 2 and 3 , the present invention offers the significant improvement of having stitching  20  backed up by continuous inter-nested folded portions of material with fold lines  48 ,  50  extending in the same direction as the upper end of support rib  3  (i.e. parallel to stitch line  20   a ), thereby eliminating point loading on the panel fabric. As mentioned, stitching  20   a - 20   c  extends through four layers of web material and defines the upper end (as well as the sides) of the rib-receiving pocket. In the unlikely event that stitching  20   a  should fail, the free end of rib  3  will shift within the rib-engaging support, with the upper blunt end of support rib  3  pressing against fold line  50 , which is in intimate contact with fold line  48 . Thus, the end of support rib  3  is supported by continuous unbroken web portions adjacent fold lines  48 ,  50 . As can be seen for example in  FIG. 4 , these fold lines are disposed within the interior of blank  12 . With reference to  FIG. 1 , stitching  22   a ,  22   b  secures the four layers of fabric together, throughout their peripheral extent. Accordingly, pressure on fold line  50  caused by the end of support rib  3  is transferred to fold line  48 . This force is in turn distributed throughout the four panels of the integral blank shown in  FIG. 4  in order to minimize local stress at the point of contact between the support rib and the rib-engaging support, thus maximizing the retention of the rib within support  10 . Thus, the length of fold lines  48 ,  50  is directly related to the width of support rib  3 . Should a support rib of greater width be desired, blank  12  can be readily adjusted to increase the length of fold lines  48 ,  50 , preferably by increasing the width of blank  12  throughout. 
     Turning now to  FIG. 15 , the rib-engaging support  10  is shown secured to a flexible sign panel  2 . With reference to  FIG. 15 , reference number  110  is applied to the intersection of stitching lines  20   a ,  20   b  and  22   a . Two intersections are shown in  FIG. 15 , one at each end of stitching line  20   a . Several additional (perimeter-attaching) lines of stitching secure the rib-engaging support  10  to the message panel. One line of stitching begins at point  110  and extends along the stitching line  22   a , to a point identified by reference number  112  located in threshold  26 . A second line of perimeter-attaching stitching extends between the remaining pair of reference points  110 ,  112  at the opposite side of the rib-engaging support. A third line of stitching indicated by reference number  114  extends between reference points  112  to secure the threshold  26  of the rib-engaging support to the flexible sign panel  2 . The perimeter attachment of rib-engaging support  10  to the flexible sign panel may also include a line of stitching at stitching line  20   a , although this relatively short amount of stitching can be omitted, if desired. In certain instances, it may be desirable to avoid overlapping one line of stitching on top of another, as described for the perimeter attaching. Accordingly, the perimeter lines of stitching joining the rib-engaging support  10  to the flexible sign panel may be moved to one side of stitching lines  20   a ,  22   a . As a further alternative, lines of stitching shown in a second alternative embodiment of  FIG. 16-18  may be employed. 
     Turning now to  FIGS. 16-18 , a second alternative embodiment of a rib-engaging support is generally indicated at  210 . As can be seen by comparing  FIGS. 1 and 16 , many features are shared between the two embodiments of rib-engaging supports identified at  10 ,  210 . Rib-engaging support  210  of the second embodiment is preferably formed from a one-piece continuous integral blank  212  shown in  FIG. 17 . By comparing the blank  212  of  FIG. 17  to the blank  12  of  FIG. 4  it can be seen that the blanks are similar, except in blank  212 , the sharp corners at the tips of the triangular ends of the panels  230 - 236  have been truncated. Preferably, stitching in the second embodiment of the rib-engaging support, joining the four panels together is essentially identical to the stitching described above with reference to the first embodiment  10  of the rib-engaging support according to principles of the present invention. Preferably, the lateral edges  260  of the rib-engaging support are not parallel to stitching lines  222   a , but rather are displaced therefrom by a relatively small acute angle. Further, the lower portions of edges  260  are truncated by relatively short vertical edges  262 . As in the first embodiment, the rib-engaging support  210  has a bottom edge  264  that is generally parallel to the upper edge  228 . 
     For purposes of comparison of the rib-engaging supports  10 ,  210  a hypothetical situation can be envisioned where stitching lines  20   a - 20   c ,  22   a  and  22   b  of  FIG. 1  are identical to stitching lines  220   a - 220   c ,  222   a  and  222   b  of  FIG. 16 . In this hypothetical comparison, the rib-engaging support  210  has additional material lying outboard of the point where stitching lines  222   a ,  222   b  meet. However, because rib-engaging support  210  omits the triangular tips present in rib-engaging support  10 , the material from which blank  212  is formed may be no wider and may even be narrower than the width of the material from which blank  12  of the first embodiment  10  is formed. Thus, as highlighted by this hypothetical comparison, it can be seen that the efficiency of the design and construction of the rib-engaging support  210  is improved in certain respects. 
     Referring now to  FIG. 17 , blank  212  is comprised of a serial succession of four panels  234 ,  230 ,  232  and  236 . Number  252  in  FIG. 17  is applied to a reference line showing the point of overlap when the panel is folded in the manner indicated in  FIGS. 16 and 18 . Number  226  is applied to an exposed portion of panel  236  which allows an improved insertion of the rib member into pocket  218  (see  FIG. 16 ). The entrance of pocket  218  is indicated by reference number  224  in  FIG. 16 . 
     The four panels of blank  212  are joined by fold lines  248 ,  246  and  250 . In the manner indicated above with respect to the first embodiment  10 , fold lines  248 ,  250  overly one another when assembled in the manner indicated for example in  FIG. 16 , and fold line  246  appears at the free edge  252  shown in  FIG. 16 . The panels  230 - 236  have opposed major surfaces indicated by a suffix “a” for the top side visible for example in  FIG. 17  and an opposed bottom side indicated by the suffix “b.” Examples of the major surfaces are indicated in the right hand portions of  FIGS. 16 and 18 . 
     Referring now to  FIG. 18 , rib-engaging support  210  is shown secured to a flexible message panel  2  by stitching lines  280 ,  282 ,  284  and  286  (which overlies stitching  220   a ). For comparison purposes, the bottom stitching line  284  shown in  FIG. 18  is substantially similar in location to the bottom stitching line  114  shown in  FIG. 15 . Preferably, stitching lines  280 ,  282  and  284  are located inboard of edges  260 ,  262  and  264 . Stitching lines  280 ,  222   a  originate at the same point  310 , with the stitching lines  280 ,  222   a  being angularly offset from one another, preferably by a relatively small acute angle less than 45°, and most preferably less than 20°. Employment of an acute angle displacement between stitching lines  280 ,  222   a  has been found to substantially alleviate or eliminate puckering of the sewn layers of panels  230 - 236  in the region of stitching line  222   a  and particularly the lower portion thereof. Preferably, the points of intersection of stitching lines  222   a ,  222   b  are spaced from the closest adjacent peripheral stitching line  282 . Although not required, it is generally preferred that the stitching lines  280  securing the support to the flexible message panel are generally parallel to the closest edge of the message panel, while the inner stitching line  222   a  is offset at an acute angle to the closest edge of the message panel as well as the adjacent stitching line  280 . 
     The arrangement of stitching lines described for rib-engaging support  210  provide a number of advantages, including an efficient distribution of forces applied to the rib-engaging support by a rib member, including a rib member which is slightly too long for the size of the flexible sign panel employed. In this latter instance, the rib member will be retained in a somewhat bowed configuration when fully installed with the flexible sign panel and allowed to come to rest. In this instance, the rib member received in pocket  218  applies an upward force to the rib-receiving pocket which tends to pull apart the overlying layers of fabric panels disposed on either side of the rib. In this instance, separating force applied by the rib will be applied along stitching lines  220   b . Angle stitching lines  220   c  provide an additional advantage in smoothly distributing the displacing force throughout the rib-engaging support, since lines  220   c  form an angle with stitching lines  220   b  that is substantially greater than 90°. The relative position of stitching lines  280 ,  222   a , taken with other features of the rib-engaging support provides an improved distribution of the force applied by the rib throughout the remainder of the rib-engaging support. 
     While rib-engaging support  10  and  21  are shown configured for use as a corner bracket in a square or diamond-shaped sign panel (see  FIG. 14 , for example), it will be readily appreciated that the rib-engaging support can be readily adapted to assume other shapes as may be desired. For example, if the rib-engaging support is required at the corner of a sign panel having an angular size other than 90°, the congruent angles of the various isosceles trapezoid panels of  FIGS. 4 and 17  can be adjusted to accommodate the alternative sign panel shape. 
     The rib-engaging support shown and described herein is preferably made from fabric material. Preferably, the fabric material of the rib-engaging support is different from the material of the sign panel, which is typically optimized for other purposes, such as adequate reflectivity mandated by federal performance standards. Accordingly, the material of rib-engaging support  10  can be optimized for strength and wear resistance and is not constrained by the choice of material or construction of the sign panel. 
     Although flexible sign panels have been described herein, it will be readily appreciated that the rib-engaging support provided by the present invention may be employed with rigid sign panels which are supported or are otherwise secured or attached to rib members. Also, packaging arrangements may benefit from the rib-engaging support of the present invention, as where elongated rib members are provided in association with an elongated package, to prevent the package from becoming bent or folded in transit. 
     While it is generally desirable to receive a support rib in the rib-engaging support with a removable “dry fit,” the rib end may be coated with a suitable adhesive before insertion in the rib-engaging pocket, to later prevent its unintentional withdrawal and so as to form a permanent connection. 
     In the examples above, each rib-engaging support receives a single rib. However, the present invention also contemplates rib-engaging supports in which multiple pockets are formed, preferably side-by-side and extending at different angles. If desired, additional layers can be stacked on top of or below the rib-engaging support for the purpose of adding more pockets to the rib-engaging support. 
     The foregoing description and the accompanying drawings are illustrative of the present invention. Still other variations and arrangements of parts are possible without departing from the spirit and scope of this invention.